NHANES
DIETARY WEB TUTORIAL
NOTES
TABLE OF CONTENTS
LET'S BEGIN -
INTRODUCTION
UNIT 1 - DIETARY DATA
SURVEY ORIENTATION
UNIT 2 - PREPARING A
DIETARY ANALYTIC
DATASET
UNIT 3 - BASIC DIETARY
ANALYSES
UNIT 4 - ADVANCED
DIETARY ANALYSES
NOTES
LET'S BEGIN
INTRODUCTION
NOTES
NHANES - Continuous NHANES Web Tutorial - Home https://www.cdc.gov/nchs/tutorials/index.htm
Main Continuous and Historical NHANES Tutorials
Continuous NHANES Tutorial (/nchs/tutorials/Nhanes/index_continuous.htm)
Everything you want and need to know about analyzing continuous (1999 and later) NHANES data is now available in a
web-based product. The Continuous NHANES Tutorial is designed to help users navigate through the dataset. Users can
browse through different modules to gain insight into NHANES data.
NHANES III Tutorial (/nchs/tutorials/Nhanes/index_III.htm)
This tutorial will orient you to NHANES III data, guide you through preparing an analytic dataset, and explain the nuances
of the survey design. Users already familiar with Continuous NHANES data and interested in using NHANES III data
should use this tutorial. New users of NHANES data should complete the Continuous NHANES tutorial before beginning
this tutorial.
NHANES II Tutorial (/nchs/tutorials/Nhanes/index_ii.htm)
This tutorial will orient you to NHANES II data, guide you through preparing an analytic dataset, and explain the nuances
of the survey design. Users already familiar with Continuous NHANES data and interested in using NHANES II data
should use this tutorial. New users of NHANES data should complete the Continuous NHANES tutorial before beginning
this tutorial.
NHANES I Tutorial (/nchs/tutorials/Nhanes/index_i.htm)
This tutorial will orient you to NHANES I data, guide you through preparing an analytic dataset, and explain the nuances
of the survey design. Users already familiar with Continuous NHANES data and interested in using NHANES I data should
use this tutorial. New users of NHANES data should complete the Continuous NHANES tutorial before beginning this
tutorial.
Special Topics
NHANES Dietary Tutorial (/nchs/tutorials/Dietary/index.htm)
This tutorial walks you through the steps of conducting an analytical project from beginning to end, with examples of many
common analytic procedures. Relevant dietary data information and nuances, tips, and explanations for SAS or SUDAAN
programs; downloadable sample program code; and analytical guidance are organized and integrated into different
modules and tasks to facilitate this learning process.
NHANES Physical Activity and Cardiovascular Fitness Data Tutorial (/nchs/tutorials/PhysicalActivity/index.htm)
This tutorial simulates a real life experience of how to conduct an analytical project from beginning to end, with a step-by-
step logical flow through typical analytic procedures. Relevant information on physical activity and cardiovascular fitness
data, nuances, tips, explanations for SAS or SUDAAN programs, downloadable sample program code, and analytical
guidance are organized and integrated into different modules and tasks to facilitate this learning process.
NHANES Environmental Chemical Data Tutorial (/nchs/tutorials/environmental/index.htm)
This tutorial will orient you to Continuous NHANES environmental chemical data, guide you through preparing an
environmental chemical analytic dataset, and explain the critical issues for the analysis of environmental chemical data.
Users already familiar with Continuous NHANES data and interested in using NHANES environmental chemical data
should use this tutorial. New users of NHANES data should complete the Continuous NHANES tutorial before beginning
this tutorial.
NHANES-CMS Linked Data Tutorial (/nchs/tutorials/NHANES-CMS/index.htm)
This tutorial walks you through the steps for conducting an analytic project using the continuous NHANES-CMS linked
data, with examples of common analytic applications and procedures. Relevant background information, tips and
explanations for SAS and SUDAAN programs, downloadable sample program code, and analytic guidance, are organized
and integrated into modules and tasks to facilitate this learning process.
Page last updated: March 29, 2012
Page last reviewed: March 29, 2012
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
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Home
Welcome to the NHANES Dietary Data Web Tutorial! The National Cancer Institute (NCI), National Center for Health
Statistics (NCHS), and U.S. Department of Agriculture (USDA) developed this tutorial to meet the growing needs of NHANES
dietary data users.
This tutorial is one of several NHANES Tutorials (/nchs/tutorials/index.htm) that have been developed to promote broader and
more proficient use of NHANES data.
WARNING
This tutorial was developed by our collaborators at the National Cancer Institute (NCI/NIH) based on NHANES data available
prior to the year 2006. Please note that when new versions of SAS or SUDAAN are released, or updates are made to NHANES
webpages and data files, this tutorial will NOT be updated accordingly. Therefore, when you use sample programs from this
tutorial, please be advised that you will need to make modifications or changes to the SAS or SUDAAN sample codes in order to
run them properly. If you have questions about this tutorial, please contact the National Cancer Institute (NCI) Applied
Research Program (http://appliedresearch.cancer.gov/about/contact.html) .
Before you get started:
Check out the Dietary Data Tutorial Roadmap (/nchs/tutorials/dietary/roadmap.htm) to orient yourself to the tutorial’s
content.
Read the Introduction (/nchs/tutorials/dietary/introduction.htm) to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go if
you need help with technical problems.
Learn about the tutorial's Objectives (/nchs/tutorials/dietary/objectives.htm) .
NHANES Dietary Data Tutorial Collaborators (/nchs/tutorials/dietary/collaborators.htm)
Clicking these logos will take you to the collaborators' websites and you will exit the NHANES Dietary Web Tutorial.
(http://riskfactor.cancer.gov/) (http://www.ars.usda.gov/ba/bhnrc/fsrg)
(http://www.cdc.gov/nchs/nhanes.htm)
Disclosure Statement
CDC, our planners, our content experts, and their spouses/partners wish to disclose they have no financial interests or other
relationships with the manufacturers of commercial products, suppliers of commercial services, or commercial supporters.
Planners have reviewed content to ensure there is no bias. CDC does not accept commercial support.
Page last updated: May 7, 2014 1/14/2019, 7:24 PM
Page last reviewed: May 7, 2014
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NHANES Dietary Web Tutorial - Introduction https://www.cdc.gov/nchs/tutorials/dietary/introduction.htm
Introduction
What are the NHANES dietary data?
The National Health and Nutrition Examination Surveys (NHANES) dietary data provide a snapshot of the food intakes and
nutritional status of the U.S. population.
more
The National Health and Nutrition Examination Surveys (NHANES) is the only national survey that collects extensive health
and nutrition information from face-to-face interviews and medical examinations. For many decades, the National Center for
Health Statistics (NCHS) and the U.S. Department of Agriculture (USDA) have collected dietary data -- NCHS always collected
dietary data as part of NHANES, whereas the USDA used its own surveys. USDA’s national food consumption surveys were
initially designed to help people achieve economical and nutritious diets. Over time, these surveys broadened in scope and
purpose to measure knowledge and attitudes about diet and health as well as to assess food and nutrient intakes.
In 2002, USDA and NCHS integrated their dietary data collection efforts and the dietary recall data are now collected in a joint
survey effort called What We Eat in America (WWEIA). These data as well as other NHANES data about dietary supplement
use, diet behaviors, and food frequency information are a valuable resource that respond to a variety of public health and
research priorities. In 2003-2006, the National Cancer Institute (NCI) supported the inclusion of a Food Frequency
Questionnaire in the NHANES to aid in the examination of usual food intakes and their relationship to health outcomes.
Click to hide
Why was this tutorial created?
The NCI, NCHS, and USDA developed this web-based tutorial to meet the growing demands of NHANES dietary data users and
to promote broader and more proficient use of NHANES dietary data.
more
Whether novice or experienced, all users face similar challenges when using NHANES dietary data due to the complexity of the
survey design and data structure. This tutorial was designed so that all users learn to:
efficiently locate pertinent information on the NCHS website, which is constantly updated and evolving;
quickly retrieve NHANES dietary data files and supplementary information, a frequent challenge given the complex
structure and large amount of data available;
correctly prepare an analytic dataset and create appropriate food and nutrient variables; and
correctly conduct statistical analyses that achieve the analyst’s research objectives with appropriate attention paid to the
nuances of the data and its complex sample design, weighting requirements, and data structure.
Click to hide
What does the tutorial provide?
This tutorial walks you through the steps of conducting an analytical project from beginning to end, with examples of many
common analytic procedures. Relevant dietary data information and nuances, tips, and explanations for SAS or SUDAAN
programs; downloadable sample program code; and analytical guidance are organized and integrated into different modules
and tasks to facilitate this learning process.
more
The tutorial is intended to be:
a step-by-step course on dietary data retrieval and analysis for new users;
a self-learning tool for novice and infrequent users to supplement their knowledge of the wide range of dietary data
available in NHANES and the analysis techniques required to properly analyze these complex datasets; and
a reference for experienced researchers highlighting NHANES analytic nuances and sample program code.
To best serve the needs of a wide range of users, this tutorial has included a large amount of information. The information is
organized in such a way that those who would like to review all information may do so, while others can efficiently bypass
sections that are not of interest to them. Overall, this tutorial provides a complete on-line learning tool.
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NHANES Dietary Web Tutorial - Introduction https://www.cdc.gov/nchs/tutorials/dietary/introduction.htm
Click to hide
What's the best way to use the tutorial?
Your own background and learning style will dictate how you can best use this tutorial.
more
If you are a beginning NHANES dietary data user, you may want to work through the tutorial in a linear fashion, starting
with the modules that orient you to the dietary data, then continuing with the modules about how to prepare an analytic
dataset and how to conduct various types of analyses.
If you are an experienced NHANES dietary data user and you are searching for specific information or types of
assistance, you can pick and choose topics of interest among the modules or even among tasks within modules.
You are encouraged to use the tutorial's features and content to suit your own needs:
a linear path for users who need step-by-step self-guided training;
index pages and easy navigation throughout modules that allow you to limit your training to information on an “as needed”
basis;
checklists, summary tables, and animated demonstrations with audio explanation to enhance learning;
real-life examples to assist you through the various processes of data preparation and data analysis;
sample code and data files for you to practice skills and run analyses using your own software;
annotated results with interpretation to help you troubleshoot your own analyses; and
links to related references and outside resources.
Click to hide
Who is the audience?
We expect users of this tutorial to come from a range of perspectives and disciplines and to have different levels of experience
with NHANES dietary data and varied degrees of skill in statistics and software packages.
more
Users will likely fall into one of these groups:
public health and other government staff involved in NHANES dietary data analyses;
researchers who use NHANES dietary data for scientific studies or educational purposes;
public health and medical professionals who use NHANES dietary data for planning, policy making, or public health
programs; and
other users of NHANES dietary data or groups interested in NHANES.
Click to hide
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
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How the Tutorial Works
The tutorial is composed of 16 modules, which are grouped into three courses. The tutorial was designed so that each module is
free-standing — you can start anywhere and move around as you wish. However, you should be aware that later modules
build on previous ones, and a greater level of statistical and epidemiologic knowledge is assumed for later modules.
All of the modules in this tutorial start in a full-screen window that shows the major tasks that will be covered. Under each Task
are several links to pop-up windows.
The "Key Concepts" link has more information about the task, including NHANES specific information and caveats to
consider.
The "How to" link provides steps for completing the task and may include demonstrations of the steps.
The "Download Sample Code and Datasets" link takes you to a page where you can download the code and datasets
used in the module.
Screenshot of Module Facepage
It is important to note that the style of some of the tasks differs from the style of other tasks, depending on the type of
information that is provided. Some tasks only have a "Key Concepts" link, whereas others have all three links mentioned above.
Additionally, some of the early modules have tasks that require you to navigate the NHANES website and are interactive.
Others provide SAS and SUDAAN programs, with explanations needed for completing the task.
When you are asked to navigate the NHANES website in a "How to" link, you will see the live NCHS website on the right side
of the screen and directions for completing the task on the left, as shown in the screenshot below. To print the
instructions, use the "Print Text!" button.
Screenshot of "Navigate" type Task
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Embedded in the "How to" instructions are links that say "Watch animation." These animations were created for those who
need additional help completing a step. Clicking this link will open a pop-up window. In this window, you will see a narrated
video demonstration of the step. If you choose not to view the demonstrations, you can bypass the animation and complete the
tasks on your own using the instructions provided. For more information on using the demonstrations, see the demonstrations
(#demostrations) section of this document.
Screenshot of Demonstration Link
Demonstrations
Adobe Flash player is required for viewing the demonstrations that show how to complete a task. See the Flash player section of
Technical and Software Requirements (techsoftwarereqs.htm#flash) for information on installing the Flash player. To view a
demonstration, click the designated link. The animation will open in a pop-up window and start playing. The slides are timed
and will advance automatically. If you wish to skip or repeat a slide, use the playback controls described in the next paragraph.
Screenshot of Playback Controls on Demonstration
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Playback controls are at the top of the animation:
Narration On/Off
/ Play/Pause
Restart
Back
Forward
Fast Forward
Return to the Logistics page (logistics.htm)
Continue to Knowledge & Skill Requirements (knowledgeskillsreqs.htm)
Page last updated: November 2, 2010
Page last reviewed: November 2, 2010
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
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Knowledge and Skill Requirements
The tutorial was structured so that you can start anywhere and move around as you wish. However, later modules build on
earlier modules and they assume some familiarity with statistics, dietary data and analysis , and nutritional epidemiologic
concepts.
Modules 1-5
These modules require:
basic familiarity with an Internet browser and computer; and
no knowledge of statistical software or programming or previous experience with NHANES dietary datasets and files.
Modules 6-11
These modules require:
basic knowledge of NHANES dietary datasets and files;
basic knowledge and skills in statistical analyses (e.g. ability to run frequently used descriptive and reference statistics, and
correctly interpret the results); and
basic knowledge and skills in SAS and/or SUDAAN statistical software.
Modules 12-16
These modules require:
basic skill in preparing an analytic dataset with NHANES dietary data;
basic knowledge of descriptive and inferential statistics, and epidemiologic concepts;
basic knowledge and skills in statistical analyses (e.g., ability to run frequently used descriptive and reference statistics,
and correctly interpret the results); and
basic knowledge and skills in SAS and/or SUDAAN statistical software.
Modules 17-22
These modules require:
basic skill in preparing an analytic dataset with NHANES dietary data;
proficiency in descriptive and inferential statistics, correlation and regression analyses methods, and epidemiologic
concepts;
proficiency in descriptive, inferential, correlation, and regression analyses (e.g., ability to run advanced statistical analyses
and correctly interpret the results);
proficiency regarding statistical considerations of dietary data analyses; and
proficiency in SAS and/or SUDAAN statistical software.
IMPORTANT NOTE
Many of the statistical methods used in this course are advanced, and may require consultation with a statistician. For modules
18-22, it is required that you have the statistical knowledge of mixed effects models, and program knowledge of calling in SAS
macros. Since Module 18 provides the background information for Modules 19-22, it is advised that you carefully read Module
18 first before tackling other modules.
Return to the Logistics page (logistics.htm)
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Page last updated: May 2, 2013
Page last reviewed: May 2, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
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NHANES Dietary Web Tutorial Roadmap
Question Module Module Name Section/Course
Number
What is this tutorial all Introduction
about?
How does this tutorial work Logistics Tutorial Home
and what knowledge and
skills do I need to complete
it?
What are the tutorial’s Objectives
learning objectives?
What topics are covered A-Z index
in the tutorial?
What types of dietary data 1 Dietary Data
are collected in NHANES? Overview
How can I find dietary and 2 Navigate NHANES
other information on the Website
NHANES website?
How are the dietary data Dietary Data Dietary Data
structured? 3 Structure & Survey
Orientation
What other dietary data Contents
resources might I need for
my research? Resources for
4 Dietary
Data Analysis
What do I need to know Overview of
about the NHANES
NHANES
survey design and 5 Survey Design and
sample weighting before I
start preparing my Weights
analytic dataset?
How do I identify and 6 Locate Variables
locate the variables I need
for my analysis?
How do I download the 7 Download Data
data and documentation Files
files I need for my
analysis?
How do I create one 8 Merge & Append Preparing a
dataset for my analysis if Datasets Dietary Analytic
I’m using data from more Dataset
than one file or more than
one 2-year survey cycle?
How do I adjust my dataset Review Data &
to accommodate missing
data, skip patterns, or 9 Create
outliers and how do I New Variables
create new variables?
What tools can I use to 10 Format & Label
describe my variables and Variables
their numeric values?
How do I permanently 11 Save a Dataset
save my dataset?
What are the statistical Identify Important
considerations peculiar to Statistical
dietary data that I need to 12 Considerations
be aware of before starting Regarding Dietary
my analysis? Data Analyses
How do I calculate Estimate Variance Basic Dietary
variance estimates and
analyze subgroups of 13 and
participants from Analyze Subgroups Analyses
NHANES?
How do I determine mean 14 Estimate Population
usual intakes of nutrients Mean Intakes
and foods?
How do I estimate ratios, 15 Estimate Ratios
including proportions and
percentages, using dietary
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data?
How do I test statistical 16 Test Hypotheses
hypotheses about
population parameters
How do I estimate the Estimate Prevalence
prevalence of dietary
of Supplement Use
supplement intake and
examine the relationship 17 and Examine
between supplement Relationships Using
intake and some health Supplement Data
measure?
What methods are Model Usual Intake
available to estimate 18 Using Dietary Recall
usual intake using
dietary recall data? Data
How do I estimate Evaluate the Effects
distributions of food or
nutrient intake? 19 of Covariates on
Usual Dietary
How do I determine the
importance of different Intakes
factors on food and
nutrient intake? Estimate Advanced Dietary
Analyses
20 Population-Level
Distributions of
Usual Dietary Intake
How do I examine the Examine the
relationship between Relationship
usual food or nutrient 21 Between Usual
intake and some Dietary Intake and
outcome measure, such Some Outcome
as body weight? Measure
How do I combine data Examine Usual
from dietary recalls and Total Nutrient
dietary supplement 22 Intake from
questionnaires to Supplements and
estimate usual total Diet
nutrient intake?
Page last updated: July 6, 2011
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
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Objectives
The list below outlines the objectives for each course in the tutorial. After completing the modules, users should be able to do
the following:
Survey Orientation
Module 1 (/nchs/tutorials/dietary/SurveyOrientation/DietaryDataOverview/intro.htm) : Dietary Data
Overview
Task 1: Describe the History of Dietary Data Collection
Task 2: Describe NHANES Dietary Data Collection Methods
Task 3: Describe Uses of the Dietary Data
Module 2 (/nchs/tutorials/dietary/SurveyOrientation/Navigate/intro.htm) : Navigate NHANES
Website
Task 1: Navigate the NHANES Homepage
Task 2: Locate Datasets on the NHANES Website
Task 3: Locate Survey Background Information
Task 4: Locate the Analytic and Reporting Guidelines
Task 5: Locate Other Useful Information on the NHANES Website
Module 3 (/nchs/tutorials/dietary/SurveyOrientation/DietaryDataStructureContents/intro.htm) :
Dietary Data Structure & Contents
Task 1: Describe How Dietary Data Fit into the NHANES Data Structure
Task 2: Describe Dietary Recall Data Files
Task 3: Describe Food Frequency Data Files
Task 4: Describe Dietary Supplement Data Files
Module 4 (/nchs/tutorials/dietary/SurveyOrientation/ResourceDietaryAnalysis/intro.htm) : Resources
for Dietary Data Analysis
Task 1: Describe the Food and Nutrient Database for Dietary Studies (FNDDS)
Task 2: Describe the USDA Food Coding Scheme
Task 3: Describe the Food Surveys Research Group (FSRG) -Defined Food Groups
Task 4: Describe the What’s In the Foods You Eat Search Tool
Task 5: Describe the MyPyramid Equivalents Database
Module 5 (/nchs/tutorials/dietary/SurveyOrientation/SurveyDesign/intro.htm) : Overview of NHANES
Survey Design and Weights
Task 1: Explain NHANES Survey Design
Task 2: Explain NHANES Sample Weights
Preparing a Dietary Analytic Dataset
Module 6 (/nchs/tutorials/dietary/Preparing/Locate/intro.htm) : Locate Variables
Task 1: Identify Dietary Recall Variables and Their File Locations
Task 2: Identify Food Frequency Variables and Their File Locations
Task 3: Identify Dietary Supplement Variables and Their File Locations
Task 4: Identify Correct Sample Weights and Their File Locations
Module 7 (/nchs/tutorials/dietary/Preparing/Download/intro.htm) : Download Data Files
Task 1: Create Folders
Task 2: Download Data Files and Documentation
Task 3: Extract and Copy NHANES Data Files in a Permanent Library
Module 8 (/nchs/tutorials/dietary/Preparing/MergeAppend/intro.htm) : Merge & Append Datasets
Task 1: Merge NHANES Data
Task 2: Append NHANES Data
Module 9 (/nchs/tutorials/dietary/Preparing/ReviewCreate/intro.htm) : Review Data & Create New
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Variables
Task 1: Identify, Recode, and Evaluate Missing Data
Task 2: Check for Skip Patterns and Explain How They Affect Results
Task 3: Check the Data for Influential Outliers
Task 4: Create New Variables
Module 10 (/nchs/tutorials/dietary/Preparing/FormatLabel/intro.htm) : Format & Label Variables
Task 1: Define and Assign Formats and Labels
Module 11 (/nchs/tutorials/dietary/Preparing/Save/intro.htm) : Save a Dataset
Task 1: Create a permanent dataset in a SAS library
Basic Dietary Analyses
Module 12 (/nchs/tutorials/dietary/Basic/StatisticalConsiderations/intro.htm) : Identify Important
Statistical Considerations Regarding Dietary Data Analyses
Task 1: Define Measurement Error
Task 2: Explain Usual Intake and Day-To-Day Variation in Dietary Intakes
Task 3: Check for Data Symmetry
Task 4: Identify Analytic Implications about Different Types of Dietary Data
Module 13 (/nchs/tutorials/dietary/Basic/EstimateVariance/intro.htm) : Estimate Variance and
Analyze Subgroups
Task 1: Use SUDAAN and SAS to Estimate Variance
Task 2: Use SUDAAN to Analyze Subgroups
Module 14 (/nchs/tutorials/dietary/Basic/PopulationMeanIntakes/intro.htm) : Estimate Population
Mean Intakes
Task 1: Estimate Mean Food Intakes
Task 2: Estimate Mean Nutrient Intakes from Foods and Beverages
Task 3: Estimate Mean Nutrient Intakes from Supplements
Task 4: Estimate Mean Total Nutrient Intakes
Module 15 (/nchs/tutorials/dietary/Basic/Ratios/intro.htm) : Estimate Ratios
Task 1: Estimate Food Sources of Nutrients
Task 2: Estimate Population-level Ratios of Intake
Module 16 (/nchs/tutorials/dietary/Basic/TestHypotheses/intro.htm) : Test Hypotheses
Task 1: Estimate Prevalence of Supplement Intake
Task 2: Estimate Distributions of Food Intake
Task 3: Estimate Distributions of Nutrient Intake
Task 4: Estimate Distributions of Total Nutrient Intake from Foods and Supplements
Advanced Dietary Analyses
Module 17 (/nchs/tutorials/dietary/advanced/EstimatePrevalence/index.htm) : Estimate Prevalence of
Supplement Use and Examine Relationships Using Supplement Data
Task 1: Estimating Prevalence of Supplement Use
Task 2: Examining the Relationship Between Supplement Use and a Categorical Outcome using a Chi-Square Test
Task 3: Examining the Relationship Between Supplement Use and a Dichotomous Outcome using Logistic Regression
Task 4: Examining the Relationship between Supplement Use and a Continuous Outcome Using a T-test
Task 5: Examining the Relationship between Supplement Use and a Continuous Outcome Using Multiple Regression
Module 18 (/nchs/tutorials/Dietary/Advanced/ModelUsualIntake/index.htm) : Model Usual Intake
Using Dietary Recall Data
Task 1: Describing Measurement Error
Task 2: Describing Statistical Methods that Have Been Used to Estimate the Distribution of Usual Intake with a Few Days of
24-hour Recalls
Task 3: Using a Unified Framework to Estimate Usual Dietary Intakes
Task 4: Using Balanced Repeated Replication to Estimate Standard Errors
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NHANES Dietary Web Tutorial - Home https://www.cdc.gov/nchs/tutorials/dietary/objectives.htm
Module 19 (/nchs/tutorials/dietary/advanced/EvaluateCovariates/index.htm) : Evaluate the Effects of
Covariates on Usual Dietary Intakes
Task 1: Evaluating the Effects of Covariates on Usual Intake of a Single Ubiquitously-Consumed Dietary Constituent
Task 2: Evaluating the Effects of Covariates on Usual Intake of a Single Episodically-Consumed Dietary Constituent
Module 20 (/nchs/tutorials/dietary/advanced/EstimateDistributions/index.htm) : Estimate
Population-Level Distributions of Usual Dietary Intake
Task 1: Estimating Distributions of Usual Intake for a Single Ubiquitously-consumed Dietary Constituent for One Population or
Subpopulation
Task 2: Estimating Distributions of Usual Intake for a Single Ubiquitously-consumed Dietary Constituent for Two or more
Subpopulations using a Covariate
Task 3: Estimating Distributions of Usual Intake for a Single Episodically-consumed Dietary Constituents
Task 4: Estimating Population Distributions of Ratios of Usual Intakes of Two Dietary Constituents that are Ubiquitously
Consumed
Module 21 (/nchs/tutorials/dietary/advanced/ExamineRelationship/index.htm) : Examine the
Relationship Between Usual Dietary Intake and Some Outcome Measure
Task 1: Describe Regression Calibration
Task 2: Examine the Relationship between Usual Intake of a Single Ubiquitously-consumed Dietary Constituent and Some
Outcome
Task 3: Examine the Relationship between Usual Intake of a Single Episodically-Consumed Dietary Constituent and Some
Outcome
Module 22 (/nchs/tutorials/dietary/advanced/ExamineUsualTotalNutrient/index.htm) : Examine Usual
Total Nutrient Intake from Supplements and Diet
Task 1: Estimate Distributions of Total Nutrient Intake
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
3 of 3 1/14/2019, 7:28 PM
NHANES Dietary Web Tutorial - Survey Orientation https://www.cdc.gov/nchs/tutorials/dietary/SurveyOrientation/intro.htm
Dietary Data Survey Orientation
The Survey Orientation course includes five modules:
Module 1. Dietary Data Overview (/nchs/tutorials/Dietary/SurveyOrientation/DietaryDataOverview/intro.htm)
Module 2. Navigate NHANES Website (/nchs/tutorials/Dietary/SurveyOrientation/Navigate/intro.htm)
Module 3. Dietary Data Structure & Contents (/nchs/tutorials/Dietary/SurveyOrientation/DietaryDataStructureContents
/intro.htm)
Module 4. Resources for Dietary Data Analysis (/nchs/tutorials/Dietary/SurveyOrientation/ResourceDietaryAnalysis
/intro.htm)
Module 5. Overview of NHANES Survey Design and Weighting (/nchs/tutorials/Dietary/SurveyOrientation
/SurveyDesign/intro.htm)
These five modules provide a general overview of the dietary data collected by the NHANES, the NHANES website, the
structure and contents of NHANES dietary data, additional databases and tools that can be used to conduct dietary analyses,
and the NHANES survey design and weighting principles. A vast amount of dietary data are organized and released in separate
data files on the NHANES and USDA websites. These data files are organized according to certain conventions. Moreover,
NHANES uses a complex sampling design with sample weights to ensure that the data are nationally representative. Therefore,
a thorough understanding of the material covered in these modules will help you be more efficient in finding the information
you need for your analysis.
Whether you are a novice or an experienced analyst, it isrecommend that you review this entire course (Modules 1-5)
before proceeding with the rest of the tutorial, as these five modules serve as a roadmap that will help you get oriented quickly
or refresh your knowledge of NHANES in general and its dietary data in particular.
Users who wish to pick and choose topics of interest in this course or throughout the tutorial may do so by using the navigation
bar to the left or by using the Tutorial A-Z Index (/nchs/tutorials/dietary/a-zindex.htm) .
The course begins with a Dietary Data Overview, where you will learn about the history and methodology of dietary data in
NHANES as well as some of the ways in which these data are used. In the next module, Navigate the NHANES Website, you
will learn where to find different documents, how to access datasets, and how to get help with NHANES data. The third
module, Data Structure & Contents, will show you how the dietary data are organized. Resources for Dietary Data Analysis
describes additional sources of food and nutrient data and provides web addresses for accessing these resources on the USDA
website. These data are often used in dietary analyses. Finally, Overview of NHANES Survey Design and Weighting describes
the complex sampling design of NHANES and explains why and how NHANES sample weights are constructed.
Before you get started:
Check out the Dietary Data Tutorial Roadmap (/nchs/tutorials/Dietary/roadmap.htm) to orient yourself to the tutorial’s
content.
Read the Introduction (/nchs/tutorials/Dietary/introduction.htm) to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go
if you need help with technical problems.
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
1 of 1 1/14/2019, 9:29 PM
NHANES Dietary Web Tutorial - Survey Orientation https://www.cdc.gov/nchs/tutorials/dietary/Preparing/intro.htm
Preparing a Dietary Analytic Dataset
Dietary data are among the most complex of all the data in NHANES. For this reason, preparing a dataset for dietary analysis
is an especially critical set of steps and often may be more time-consuming than the analysis itself.
Analysts working with NHANES dietary data frequently want to be able to answer the following types of questions:
What is the mean intake of a given food?
What is the mean intake of a given nutrient from all foods and beverages?
What is the mean intake of a given nutrient from supplements?
Which foods are the major sources of a given nutrient?
What is the distribution of intake of a given food or nutrient across a selected population?
How does dietary intake relate to some health parameter?
To conduct these analyses, you will first need to know how to successfully complete the tasks described in the following
modules of the Preparing an Analytic Dataset course:
Module 6. Locate Variables (/nchs/tutorials/Dietary/Preparing/Locate/intro.htm)
Module 7. Download Data Files (/nchs/tutorials/Dietary/Preparing/Download/intro.htm)
Module 8. Merge & Append Datasets (/nchs/tutorials/Dietary/Preparing/MergeAppend/intro.htm)
Module 9. Review Data & Create New Variables (/nchs/tutorials/Dietary/Preparing/ReviewCreate/intro.htm)
Module 10. Format & Label Variables (/nchs/tutorials/Dietary/Preparing/FormatLabel/intro.htm)
Module 11. Save a Dataset (/nchs/tutorials/Dietary/Preparing/Save/intro.htm)
As you work your way through these modules, and eventually prepare your own analytic dataset, it is useful to keep in mind
three issues that add to the challenge of dietary data analysis—the unit of analysis, variable definitions, and the
inferred population. All of these issues require that you think very specifically about your research question.
IMPORTANT NOTE
This tutorial uses the SAS convention of using the term "variable" to refer to a field in a dataset.
One of the reasons that dietary data are so complex is because the unit of analysis may vary. The basic unit of analysis in
NHANES is the individual participant, identified by the variable SEQN. However, because of the way the dietary data are
structured—with individuals having multiple food and dietary supplement records, which in turn have their own
accompanying sets of variables—the unit of analysis for some types of analyses is at the level of the food or supplement,
rather than the individual.
Dietary data also are challenging to work with because many analyses require the creation of new variables from variables
that are found in the survey data files. For example, if you are interested in finding the answer to the question “What is the
mean intake of milk among survey participants?,” the way you define “milk” (e.g., all types of fluid milk consumed as a
beverage, or milk also consumed as an ingredient in other foods, or servings of milk as defined by the guidance in
MyPyramid) may require you to create several new variables based on your analytic needs.
IMPORTANT NOTE
The modules in this course require some basic knowledge of statistics as well as statistical software (e.g. SAS and SUDAAN)
and programming.
Before you get started
Review the Dietary Data Survey Orientation course (/nchs/tutorials/dietary/SurveyOrientation/intro.htm) .
If you have questions about this tutorial as a whole:
Check out the Dietary Data Tutorial Roadmap (/nchs/tutorials/dietary/roadmap.htm) to orient yourself to the tutorial’s
1 of 2 1/14/2019, 9:29 PM
NHANES Dietary Web Tutorial - Survey Orientation https://www.cdc.gov/nchs/tutorials/dietary/Preparing/intro.htm
content.
Read the Introduction (/nchs/tutorials/dietary/introduction.htm) to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go if
you need help with technical problems.
Sample Code
Abbreviated SAS and SUDAAN code is presented throughout the tutorial for the sole purpose of demonstrating and explaining
specific steps in an analysis. The abbreviated code does not comprise a complete SAS or SUDAAN program that can be readily
submitted for a computer run. If you need the complete SAS or SUDAAN program, please consult the Additional Resources
section of this tutorial.
Before you get started
Check out the Dietary Data Tutorial Roadmap (/nchs/tutorials/dietary/roadmap.htm) to orient yourself to the tutorial’s
content.
Read the Introduction (/nchs/tutorials/dietary/introduction.htm) to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go if
you need help with technical problems.
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
2 of 2 1/14/2019, 9:29 PM
NHANES Dietary Web Tutorial - Survey Orientation https://www.cdc.gov/nchs/tutorials/dietary/Basic/intro.htm
Basic Dietary Analyses
The Basic Dietary Analyses course contains 5 modules:
Module 12. Identify Important Statistical Considerations Regarding Dietary Data Analyses (/nchs/tutorials/Dietary
/Basic/StatisticalConsiderations/intro.htm)
Module 13. Estimate Variance, Analyze Subgroups, and Calculate Degrees of Freedom (/nchs/tutorials/Dietary/Basic
/EstimateVariance/intro.htm)
Module 14. Estimate Population Mean Intakes (/nchs/tutorials/Dietary/Basic/PopulationMeanIntakes/intro.htm)
Module 15. Estimate Ratios (/nchs/tutorials/Dietary/Basic/Ratios/intro.htm)
Module 16. Test Hypotheses (/nchs/tutorials/Dietary/Basic/TestHypotheses/intro.htm)
These five modules demonstrate how to perform some of the most frequently requested analyses of NHANES dietary data. The
course begins with a description of the particular idiosyncrasies of dietary data, especially measurement error and its relevance
to the interpretation of results. The next module continues the statistical theme by showing how to estimate variances, analyze
subgroups, and calculate degrees of freedom, given the NHANES sampling design. The remaining modules demonstrate how
to perform selected basic analyses with dietary data.
The course is aimed at specific issues surrounding dietary analysis. If you are interested in learning more about the basics of
estimating means and prevalences, conducting t-tests or chi-square tests, generating confidence intervals, or performing age
standardization or regression analyses, please see the Continuous NHANES Web Tutorial, NHANES Analysis Course (/nchs
/tutorials/Nhanes/NHANESAnalyses/NHANES_Analyses_intro.htm) .
If you are an experienced analyst who needs only specific information to help you complete an analysis on your own, you can
pick and choose topics of interest from the navigation bar to the left, or from the Tutorial A-Z Index (/nchs/tutorials/dietary/A-
Zindex.htm) . You may also go to the Sample Code and Datasets page (/nchs/tutorials/dietary/Downloads/downloads.htm) to
download and modify sample programs and datasets for your own use.
Sample Code
Abbreviated SAS and SUDAAN code is presented throughout the tutorial for the sole purpose of demonstrating and explaining
specific steps in an analysis. The abbreviated code does not comprise a complete SAS or SUDAAN program that can be readily
submitted for a computer run. If you need the complete SAS or SUDAAN program, please consult the Additional Resources
section of this tutorial.
Before you get started
Check out the Dietary Data Tutorial Roadmap (/nchs/tutorials/dietary/roadmap.htm) to orient yourself to the tutorial’s
content.
Read the Introduction (/nchs/tutorials/dietary/introduction.htm) to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go if
you need help with technical problems.
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
1 of 1 1/14/2019, 9:30 PM
NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/advanced/index.htm
Advanced Dietary Analyses
The Advanced Dietary Analyses course contains 6 modules:
Module 17. Estimate Prevalence of Supplement Use and Examine Relationships Using Supplement Data (/nchs
/tutorials/dietary/advanced/EstimatePrevalence/index.htm)
Module 18. Model Usual Intake Using Dietary Recall Data (/nchs/tutorials/Dietary/Advanced/ModelUsualIntake
/index.htm)
Module 19. Evaluate the Effects of Covariates on Usual Dietary Intakes (/nchs/tutorials/dietary/advanced
/EvaluateCovariates/index.htm)
Module 20. Estimate Population-Level Distributions of Usual Dietary Intake (/nchs/Tutorials/Dietary/Advanced
/EstimateDistributions/index.htm)
Module 21. Examine the Relationship Between Usual Dietary Intake and Some Outcome Measure (/nchs/tutorials
/dietary/advanced/ExamineRelationship/index.htm)
Module 22. Examine Usual Total Nutrient Intake from Supplements and Diet (/nchs/tutorials/dietary/advanced
/ExamineUsualTotalNutrient/index.htm)
These six modules describe techniques for estimating usual intake of dietary and supplement intake, how dietary intakes vary
among individuals, and how individual intakes relate to other factors.
Most modules in this course distinguish between two types of dietary constituents depending upon the frequency with which
they are consumed by most individuals. Those that are consumed on a daily or almost daily basis, such as nutrients like
calcium, are referred to as “ubiquitously consumed” dietary constituents. Some food groups, such as total grains, are also
ubiquitously consumed. Dietary constituents that are consumed on a less frequent basis, such as most foods and some food
groups (e.g., dark green vegetables) and some nutrients, are referred to as “episodically consumed”.
Many of the statistical methods used in this course are advanced, and may require consultation with a statistician. The course
begins with a description of analyses using the categorical-level dietary supplement data, which is presented first because the
statistical techniques are relatively straightforward (Module 17). It then describes a unified approach to estimate usual dietary
intakes of both ubiquitously-consumed and episodically-consumed dietary constituents from 24-hour recall data (Module 18).
The unified approach can be used for a variety of applications that are described in subsequent modules: evaluating the effects
of covariates on usual dietary intakes (Module 19), estimating population-level distributions of usual food and nutrient intake
(Module 20), examining the relationship between usual dietary intake and health outcomes (Module 21), and examining total
nutrient intake from food and dietary supplements (Module 22).
IMPORTANT NOTE
Many of the statistical methods used in this course are advanced, and may require consultation with a statistician. For modules
18-22, it is required that you have the statistical knowledge of mixed effects models, and program knowledge of calling in SAS
macros. Since Module 18 provides the background information for Modules 19-22, it is advised that you carefully read Module
18 first before tackling other modules.
The material presented in the Advanced Dietary Analyses Web Tutorial Course was developed for NHANES 2003-2006, which
obtained two 24-hour recalls on the participants and collected dietary supplement data in the household interview. Data from
NHANES 2003-2004 is used in the examples given in the course.
The course is aimed at specific issues surrounding usual dietary intake analysis. If you are interested in learning more about the
basics of estimating distributions and examining relationships among variables in NHANES, please see the section on
“NHANES Analysis” course on the Continuous NHANES Web Tutorial Home page.
Users of this tutorial are expected to have a command of the material presented in the Basic Dietary Analysis Course (/nchs
/tutorials/dietary/basic/index.htm) .
If you are an experienced analyst who only needs specific information to help you complete an analysis on your own, you can
choose topics of interest from the navigation bar to the left, or from the Tutorial A-Z Index (/nchs/tutorials/dietary/a-zindex.htm) .
You may also go to the Sample Code and Datasets page (/nchs/tutorials/dietary/downloads/downloads.htm) to download and
modify sample programs and datasets for your own use.
Sample Code
Abbreviated SAS and SUDAAN code is presented throughout the course for the sole purpose of demonstration and explanation.
The abbreviated code does not comprise a complete SAS or SUDAAN program that can be readily submitted for a computer
run. If you need the complete SAS or SUDAAN program, please consult the Download Sample Code and Dataset (/nchs/tutorials
/dietary/downloads/downloads.htm) links listed under the tasks in the respective module.
Before you get started
1 of 2 1/14/2019, 9:30 PM
NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/advanced/index.htm
Check out the NHANES Dietary Web Tutorial Roadmap (/nchs/tutorials/dietary/roadmap.htm) section to orient yourself to
the tutorial’s content
Read the Introduction (/nchs/tutorials/dietary/introduction.htm) section to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go if
you need help with technical problems.
Learn about the tutorial's Learning Objectives (/nchs/tutorials/dietary/objectives.htm)
Page last updated: July 20, 2011
Page last reviewed: July 20, 2011
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
2 of 2 1/14/2019, 9:30 PM
NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/downloads/downloads.htm
Sample Programs and Datasets
Right-click the program or dataset you want to download. Then select "Save Target As" from the pop-up menu and save the
program or dataset to your computer. Left-clicking the examples may result in garbled text being displayed as the browser tries
to interpret the file.
The datasets are intended to be used with the tutorial only, as they may contain a subset of the variables available. If you wish
to conduct your own analyses, please download the most current and complete datasets from the NHANES website.
WARNING
This tutorial was developed by our collaborators at the National Cancer Institute (NCI/NIH) based on NHANES data available
prior to the year 2006. Please note that when new versions of SAS or SUDAAN are released, or updates are made to NHANES
webpages and data files, this tutorial will NOT be updated accordingly. Therefore, when you use sample programs from this
tutorial, please be advised that you will need to make modifications or changes to the SAS or SUDAAN sample codes in order to
run them properly. If you have questions about this tutorial, please contact the National Cancer Institute (NCI) Applied
Research Program (http://appliedresearch.cancer.gov/about/contact.html) .
Programs and Output
Module Task Sample SAS Code SAS Output SUDAAN Code SUDAAN Output
Program
FFQMerge SAS Code [SAS - 1 SAS Code [SAS - 1 KB]
Program KB] (ftp://ftp.cdc.gov (ftp://ftp.cdc.gov
/pub/Health_Statistics
/pub/Health_Statistics
/nchs/nhanes /nchs/nhanes/2003-2004
/2003-2004
/ffqmergecode_c.txt) /ffqmergecode_c.txt)
SAS Code [SAS - 9 SAS Output [PDF - 12 SUDAAN Code [SAS - 9 SUDAAN Output [PDF -
23 KB] (/nchs/tutorials
Milk Program KB] (/nchs/tutorials KB] (/nchs/tutorials KB] (/nchs/tutorials /Dietary/Downloads
/milk_SUDAAN.PDF
/Dietary/Downloads /Dietary/Downloads /Dietary/Downloads
/milk_SAS.sas) /milk_SAS.PDF) /milk_SUDAAN.sas)
Food Source SAS Code [SAS - 12 SAS Output [PDF - SUDAAN Code [SAS - 12 SUDAAN Output [PDF -
Program KB] (/nchs/tutorials 40 KB] (/nchs KB] (/nchs/tutorials 35 KB] (/nchs/tutorials
/Dietary/Downloads /Dietary/Downloads /Dietary/Downloads
/foodsrces_SAS.sas) /tutorials/Dietary /foodsrces_SUDAAN.pdf
/Downloads /foodsrces_SUDAAN.sas)
/foodsrces_SAS.PDF)
Total Calcium SAS Code [SAS - 4 SAS Output [PDF - 8 N/A N/A
Program KB (/nchs/tutorials KB (/nchs/tutorials
/Dietary/Downloads /Dietary/Downloads
/total_calc.PDF)
/total_calc.sas)
SAS Code [SAS - 24 SAS Output [PDF - SUDAAN Code [SAS - 25 SUDAAN Output [SAS -
Supplement KB] (/nchs/tutorials 47 KB] (/nchs/tutorials KB] (/nchs/tutorials 50 KB] (/nchs/tutorials
Program
/Dietary/Downloads /Dietary/Downloads /Dietary/Downloads /Dietary/Downloads
/supplement_SAS.sas) /supplement_SAS.PDF) /supplement_SUDAAN.sas) /supplement_SUDAAN.PDF
Outliers SAS Code [SAS - 3 SAS Output [PDF - 9 N/A N/A
Program KB] (/nchs/tutorials KB] (/nchs/tutorials
/Dietary/Downloads /Dietary/Downloads
/outlier.sas) /outlier.PDF)
Estimate SAS Code [SAS - 2 SAS Output [PDF - 21 SUDAAN Code [SAS - 2 SUDAAN Output [PDF -
Prevalence of KB] (/nchs/tutorials 21 KB] (/nchs/tutorials
17 1 Supplement /dietary/Downloads KB] (/nchs/tutorials KB] (/nchs/tutorials
/dietary/Downloads/mod17
Use Using /mod17 task1b /dietary/Downloads /dietary/Downloads/mod17 task1a SUDAAN.pdf)
Proportions SAS.sas)
/mod17 task1b SAS.pdf) task1a SUDAAN.sas)
Program
Calculate a Chi- SAS Code [SAS - 2 SAS Output [PDF - SUDAAN Code [SAS - 2 SUDAAN Output [PDF -
Square Test KB] (/nchs/tutorials 28 KB] (/nchs
17 2 Program /dietary/Downloads KB] (/nchs/tutorials 24 KB] (/nchs/tutorials
/tutorials/dietary
/mod17 task2a /Downloads/mod17 /dietary/Downloads/mod17 /dietary/Downloads/mod17
SAS.sas)
task2a SAS.pdf) task2b SUDAAN.sas) task2b SUDAAN.pdf)
Perform SAS Code [SAS - 3 SAS Output [PDF - SUDAAN Code [SAS - 4 SUDAAN Output [PDF -
17 3 Logistic KB] (/nchs/tutorials 25 KB] (/nchs KB] (/nchs/tutorials 37 KB] (/nchs/tutorials
Regression /dietary/Downloads /tutorials/dietary /dietary/Downloads/mod17 /dietary/Downloads/mod17
1 of 4 1/14/2019, 9:31 PM
NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/downloads/downloads.htm
Module Task Sample SAS Code SAS Output SUDAAN Code SUDAAN Output
Program
Program /mod17 task3b /Downloads/mod17 task3a SUDAAN.sas) task3a SUDAAN.pdf)
SAS.sas) task3b SAS.pdf)
Set Up a T-Test SAS Code [SAS - 2 SAS Output [PDF - SUDAAN Code [SAS - 3 SUDAAN Output [PDF -
in NHANES KB] (/nchs/tutorials 24 KB] (/nchs
17 4 Program /dietary/Downloads KB] (/nchs/tutorials 23 KB] (/nchs/tutorials
/tutorials/dietary
/mod17 task4b /Downloads/mod17 /dietary/Downloads/mod17 /dietary/Downloads/mod17
SAS.sas)
task4b SAS.pdf) task4a SUDAAN.sas) task4a SUDAAN.pdf)
SAS Code [SAS - 3 SAS Output [PDF - SUDAAN Code [SAS - 3 SUDAAN Output [PDF -
28 KB] (/nchs
Perform Linear KB] (/nchs/tutorials KB] (/nchs/tutorials 31 KB] (/nchs/tutorials
/tutorials/dietary
17 5 Regression /dietary/Downloads /Downloads/mod17 /dietary/Downloads/mod17 /dietary/Downloads/mod17
Program /mod17 task5b task5b SAS.pdf) task5a SUDAAN.sas) task5a SUDAAN.pdf)
SAS.sas)
Estimate
18 4 Standard SAS Code [SAS - 2 SAS Output [PDF - 18 N/A N/A
Errors with KB] (/nchs/tutorials KB] (/nchs/tutorials
/dietary/Downloads /dietary/Downloads
Balanced /mod18 task4 SAS.sas) /mod18 task4 SAS.pdf)
Repeated
Replication
(BRR) Program
Evaluate the
Effects of
Covariates on SAS Output [PDF -
266 KB] (/nchs
Usual Intake of SAS Code [SAS - 9 /tutorials/dietary
19 1 a Single KB] (/nchs/tutorials /Downloads/mod19 N/A N/A
task1 SAS.pdf)
Ubiquitously- /dietary/Downloads
Consumed /mod19 task1 SAS.sas)
Dietary
Constituent
Program
Evaluate the
Effects of
Covariates on SAS Output [PDF -
923 KB] (/nchs
Usual Intake of SAS Code [SAS - 12 /tutorials/dietary
19 2 a Single KB] (/nchs/tutorials /Downloads/mod19 N/A N/A
task2 SAS.pdf)
Episodically- /dietary/Downloads
Consumed /mod19 task2 SAS.sas)
Dietary
Constituent
Program
Estimate the
Distribution of
Usual Intake
for a Single
Ubiquitously- SAS Output [PDF -
107 KB] (/nchs
consumed SAS Code [SAS - 10 /tutorials/dietary
20 1 Dietary KB] (/nchs/tutorials /Downloads/mod20 N/A N/A
task1 SAS.pdf)
Constituent for /dietary/Downloads
One Population /mod20 task1 SAS.sas)
or
Subpopulation
using the NCI
Method
Program
Estimate
Distributions
of Usual Intake SAS Output [PDF -
142 KB] (/nchs
20 2 for a Single SAS Code [SAS - 10 /tutorials/dietary N/A N/A
Ubiquitously- KB] (/nchs/tutorials
/dietary/Downloads /Downloads/mod20
consumed /mod20 task2 SAS.sas) Task2 SAS.pdf)
Dietary
Constituent
with a Few
Days of 24-
2 of 4 1/14/2019, 9:31 PM
NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/downloads/downloads.htm
Module Task Sample SAS Code SAS Output SUDAAN Code SUDAAN Output
Program N/A N/A
N/A N/A
hour Recalls N/A N/A
for N/A N/A
N/A N/A
Subpopulations
using a
Covariate
Program
Estimate
Distributions
of Usual Intake
20 3 for a Single SAS Code [SAS - 10 SAS Output [PDF -
Episodically- KB] (/nchs/tutorials 257 KB] (/nchs
/dietary/Downloads /tutorials/dietary
consumed /mod20 task3 SAS.sas)
Dietary /Downloads/mod20
task3 SAS.pdf)
Constituent
using the NCI
Method
Program
Estimate
Distributions
of Usual Intake
20 4 for the Ratio of SAS Code [SAS - 23 SAS Output [PDF -
Two KB] (/nchs/tutorials 263 KB] (/nchs
/dietary/Downloads /tutorials/dietary
Ubiquitously-
consumed /mod20 task4 /Downloads/mod20
Dietary SAS.SAS) task4 SAS.pdf)
Constituent
Using the NCI
Method
Program
Examine the
Relationship
Between Usual
21 2 Intake of a SAS Code [SAS - 17 SAS Output [PDF -
Single KB] (/nchs/tutorials 28 KB] (/nchs
/dietary/Downloads
Ubiquitously- /mod21 task2 SAS.sas) /tutorials/dietary
Consumed /Downloads/mod21
Dietary
Constituent task2 SAS.pdf)
and Some
Outcome
Program
Examine the
Relationship
Between Usual
Intake of a SAS Output [PDF -
34 KB] (/nchs
21 3 Single SAS Code [SAS - 15
Episodically- KB] (/nchs/tutorials /tutorials/dietary
/dietary/Downloads /Downloads/mod21
consumed /mod21 task3 SAS.sas)
Dietary task3 SAS.pdf)
Constituent
and Some
Outcome
Program
22 1 Estimate SAS Code [SAS - 19 SAS Output [PDF - 61
Distributions KB] (/nchs/tutorials KB] (/nchs/tutorials
/dietary/Downloads /dietary/Downloads
of Total /mod22 task1 SAS.sas) /mod22 task1 SAS.pdf)
Nutrient Intake
Program
Datasets
calcmilk.sas7bdat (/nchs/tutorials/Dietary/Downloads/calcmilk.sas7bdat) [SAS7BDAT - 809 KB]
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NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/downloads/downloads.htm
demoadv.sas7bdat (/nchs/tutorials/dietary/Downloads/demoadv.sas7bdat) [SAS7BDAT - 5.7 MB]
demo_b.sas7bdat (/nchs/tutorials/Dietary/Downloads/demo_b.sas7bdat) [SAS7BDAT - 2.0 MB]
demo_c.sas7bdat (/nchs/tutorials/Dietary/Downloads/demo_c.sas7bdat) [SAS7BDAT - 2.5 MB]
demoosts.sas7bdat (/nchs/tutorials/Dietary/Downloads/demoosts.sas7bdat) [SAS7BDAT - 1.5 MB]
dr1iff_c.sas7bdat (/nchs/tutorials/Dietary/Downloads/dr1iff_c.sas7bdat) [SAS7BDAT - 85.4 MB]
dr1tot_c.sas7bdat (/nchs/tutorials/Dietary/Downloads/dr1tot_c.sas7bdat) [SAS7BDAT - 12.5 MB]
drxiff_b.sas7bdat (/nchs/tutorials/Dietary/Downloads/drxiff_b.sas7bdat) [SAS7BDAT - 82.7 MB]
dsq1_c.sas7bdat (/nchs/tutorials/Dietary/Downloads/dsq1_c.sas7bdat) [SAS7BDAT - 405 KB]
dsq2_c.sas7bdat (/nchs/tutorials/Dietary/Downloads/dsq2_c.sas7bdat) [SAS7BDAT - 737 KB]
DSPI.sas7bdat (/nchs/tutorials/Dietary/Downloads/dsq3_c.sas7bdat) [SAS7BDAT - 217 KB]
DSII.sas7bdat (/nchs/tutorials/Dietary/Downloads/dsq4_c.sas7bdat) [SAS7BDAT - 1.4 MB]
osq_c.sas7bdat (/nchs/tutorials/Dietary/Downloads/osq_c.sas7bdat) [SAS7BDAT - 2.2 MB]
osteo_analysis_data.sas7bdat (/nchs/tutorials/Dietary/Downloads/osteo_analysis_data.sas7bdat) [SAS7BDAT - 5 KB]
Page last updated: May 7, 2014
Page last reviewed: May 7, 2014
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
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NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/AdditionalResources/referenc...
Key References
These references are used throughout the tutorial. Links to abstracts on PubMed or the full text of the publications have been
created when available.
History of Dietary Data Collection
Briefel RR. Assessment of the US diet in national nutrition surveys: national collaborative efforts and NHANES. Am J Clin
Nutr 1994;59(1 Suppl):164S-167S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/8279416?ordinalpos=6&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Kohlmeier L. Dietary methodology considerations for NHANES III. Vital Health Stat 4 1992;(27):81-84.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/1375417?ordinalpos=16&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Liu K. Statistical issues related to the design of dietary survey methodology for NHANES III. Vital Health Stat 4 1992(27):3-14;
discussion 15-23.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/1375411?ordinalpos=7&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
McDowell MA, Briefel RR. The Dietary Data Collection System: automated interview and coding system for NHANES III.
Proceedings-Fourteenth National Nutrient Databank Conference. 1989. Iowa City, IA.
Full text (NNDB94.pdf)
McDowell MA. The NHANES III Supplemental Nutrition Survey of Older Americans. Am J Clin Nutr 1994;59(1
Suppl):224S-226S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/8279430?ordinalpos=7&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Sempos CT, Briefel RR, Johnson C, Woteki CE. Process and rationale for selecting dietary methods for NHANES III. Vital
Health Stat 4 1992;(27):85-90.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/1375418?ordinalpos=8&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Tippett KS, Enns CW, Moshfegh AJ. Food consumption surveys in the U.S. Department of Agriculture. Nutr Today
1999;34;33-46
Abstract
Woteki CE, Briefel R, Hitchcock D, Ezzati T, Maurer K. Selection of nutrition status indicators for field surveys: the NHANES
III design. J Nutr 1990;120 Suppl 11:1440-1445.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/2243284?ordinalpos=4&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
NHANES Dietary Data Collection
24-Hour Recall Data
Blanton CA, Moshfegh AJ, Baer DJ, Kretsch MJ. The USDA Automated Multiple-Pass Method accurately estimates group total
energy and nutrient intakes. J Nutr 2006;136(10):2594-2599.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/16988132?ordinalpos=1&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
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Conway JM, Ingwersen LA, Moshfegh AJ. Accuracy of dietary recall using the USDA five-step multiple-pass method in men:
an observational validation study. J Am Diet Assoc 2004;104(4):595-603.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/15054345?ordinalpos=1&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Dwyer J, Picciano MF, Raiten DJ, Members of the Steering Committee: National Health and Nutrition Examination Survey.
Collection of food and dietary supplement intake data: What We Eat in America—NHANES. J Nutr 2003;133(2):590S-600S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12566509?ordinalpos=6&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Raper N, Perloff B, Ingwersen L, Steinfeldt L, Anand J. An overview of USDA’s Dietary Intake Data System. J Food Compos
Anal 2004;17(3-4):545-555.
Abstract
Food Frequency Data
Subar AF, Dodd KW, Guenther PM, Kipnis V, Midthune D, McDowell M, Tooze JA, Freedman LS, Krebs-Smith SM. The food
propensity questionnaire: concept, development, and validation for use as a covariate in a model to estimate usual food intake.
J Am Diet Assoc 2006;106(10):1556-1563.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/17000188?ordinalpos=4&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Briefel RR, Flegal KM, Winn DM, Loria CM, Johnson CL, Sempos CT. Assessing the nation's diet: limitations of the food
frequency questionnaire. J Am Diet Assoc. 1992 Aug;92(8):959-62.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/1640039?ordinalpos=2&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Dietary Supplement Data
Dwyer J, Picciano MF, Raiten DJ, Members of the Steering Committee: National Health and Nutrition Examination Survey.
Collection of food and dietary supplement intake data: What We Eat in America—NHANES. J Nutr 2003;133(2):590S-600S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12566509?ordinalpos=6&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Radimer KL. Methodological issues in assessing dietary supplement use in children. J Am Diet Assoc 2005;105(5):703-708.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/15883544?ordinalpos=2&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Radimer KL. National nutrition data: contributions and challenges to monitoring dietary supplement use in women. J Nutr
2003;133(6):2003S-2007S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12771354?ordinalpos=4&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Uses of the Dietary Data
Moshfegh AJ. The National Nutrition Monitoring and Related Research Program: progress and activities. J Nutr 1994;124(9
Suppl):1843S-1845S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/8089760?ordinalpos=15&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Murphy SP. Collection and analysis of intake data from the integrated survey. J Nutr 2003;133(2):585S-589S.
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Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12566508?ordinalpos=25&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Radimer K, Bindewald B, Hughes J, Ervin B, Swanson C, Picciano MF. Dietary supplement use by US adults: data from the
National Health and Nutrition Examination Survey, 1999-2000. Am J Epidemiol 2004;160(4):339-349.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/15286019?ordinalpos=3&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Rock CL. Multivitamin-multimineral supplements: who uses them? Am J Clin Nutr 2007;85(1):277S-279S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/17209209?ordinalpos=22&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Woteki C. Integrated NHANES: uses in national policy. J Nut 2003;133(2):582S-584S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12566507?ordinalpos=4&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Woteki CE, Briefel RR, Klein CJ, Jacques PF, Kris-Etherton PM, Mares-Perlman JA, Meyers LD. Nutrition monitoring:
summary of a statement from an American Society for Nutritional Sciences working group. J Nutr 2002;132(12):3782-3783.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12468623?ordinalpos=1&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Food and Nutrient Database for Dietary Studies (FNDDS)
Dwyer J, Picciano MF, Raiten DJ, Members of the Steering Committee: National Health and Nutrition Examination Survey.
Collection of food and dietary supplement intake data: What We Eat in America—NHANES. J Nutr 2003;133(2):590S-600S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12566509?ordinalpos=6&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Loria CM, McDowell MA, Johnson CL, Woteki CE. Nutrient data for Mexican-American foods: are current data adequate? J
Am Diet Assoc 1991;91(8):919-922.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/1894898?ordinalpos=5&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Important Considerations Regarding Dietary Data Analyses
Beaton GH. Approaches to analysis of dietary data: relationship between planned analyses and choice of methodology. Am J
Clin Nutr 1994:59(suppl 1):253S-261S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/8279436?ordinalpos=4&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Beaton, GH. Errors in the interpretation of dietary assessments. Am J Clin Nutr 1997:65(4 suppl):1100S-1107S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/9094905?ordinalpos=2&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Estimating Population Ratios of Intake
Krebs-Smith, SM, PS Kott, PM Guenther. Mean proportion and population proportion: two answers to the same question? J
Am Diet Assoc 1989;89(5):671-676.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/2723291?ordinalpos=2&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
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Estimating Population-level Distributions and Prevalence of Intake
Carriquiry AL. Estimation of usual intake distributions of nutrients and foods. J Nutr 2003;133(22):601S-608S.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/12566510?ordinalpos=8&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
National Research Council. Nutrient Adequacy: Assessment Using Food Consumption Surveys. 1986. Washington, D.C.,
National Academy Press.
Nusser SM, Carriquiry AL, Dodd KW, Fuller WA. A semi-parametric transformation approach to estimating usual nutrient
intake distributions. Journal of the American Statistical Association 1996; 91:1440-1449.
Dodd KW. A Technical Guide to C-SIDE: Software for Intake Distribution Estimation. 1996. Technical Report 96-TR 32,
Dietary Assessment Research Series Report 9, Department of Statistics and Center for Agricultural and Rural Development.
Iowa State University.
Tooze JA, Midthune D, Dodd KW, Krebs-Smith SM, Subar AF, Carroll RJ, Kipnis V. A New Statistical Method for Estimating
the Distribution of Usual Intake of Episodically Consumed Foods, Journal of the American Dietetics Association
2006;106(10):1575-87.
Dodd KW, Guenther PM, Freedman LS, Subar AF, Kipnis V, Midthune D, Tooze JA, Krebs-Smith SM. Statistical methods for
estimating usual intake of nutrients and foods: a review of the theory. Journal of the American Dietetics Association 2006
Oct;106(10):1575-87.
Freedman LS, Guenther PM, Dodd KW, Krebs-Smith SM, Midthune D. The population distribution of ratios of usual intakes of
dietary components that are consumed every day can be estimated from repeated 24-hour recalls. J Nutr. 2010
Jan;140(1):111-6.
Freedman LS, Guenther PM, Krebs-Smith SM, Dodd KW, Midthune D. A population's distribution of Healthy Eating
Index-2005 component scores can be estimated when more than one 24-hour recall is available. J Nutr. 2010
Aug;140(8):1529-34.
Examining the Relationship Between Dietary Intake and Some Outcome Measure
Tarasuk VS, Brooker A-S. Interpreting epidemiologic studies of diet-disease relationships. J Nutr 1997;127(9):1847-1852.
Abstract (http://www.ncbi.nlm.nih.gov/pubmed/9278571?ordinalpos=1&
itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum)
Carroll RJ, Ruppert D, Stefanski LA, Crainiceanu CM. Measurement Error in Nonlinear Models, 2nd ed. Boca Raton:
Chapman & Hall, 2006.
Kipnis V, Midthune D, Buckman DW, Dodd KW, Guenther PM, Krebs-Smith SM, Subar AF, Tooze JA, Carroll RJ, Freedman
LS. Modeling data with excess zeros and measurement error: application to evaluating relationships between episodically
consumed foods and health outcomes, Biometrics 2009;65:1003-1010.
Rosner B, Willett WC, Spiegelman D. Correction of logistic regression relative risk estimates and confidence intervals for
systemtic with-person measurement error. Statisics in Medicine 1989;8:1051-1069.
Kipnis V, Midthune D, Buckman DW, Dodd KW, Guenther PM, Krebs-Smith SM, Subar AF, Tooze JA, Carroll RJ, Freedman
LS. Modeling data with excess zeros and measurement error: application to evaluating relationships between episodically
consumed foods and health outcomes. Biometrics 2009;65:1003-1010.
Page last updated: May 3, 2013
Page last reviewed: November 10, 200 9
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
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Information About Dietary Variables
As described in the Locate Variables module, NHANES dietary, food frequency, and supplement variables and information
about the variables, are stored in different data and documentation files. The Locate Variables (/nchs/tutorials/dietary/Preparing
/Locate/intro.htm) module provides lists of variables that are commonly included in dietary analyses. This page provides
additional information on these variables. Please note, however, that the most complete descriptions of these variables can be
found in the Analytic Notes section of the “Docs” files.
Dietary Recall Variables
Dietary Recall Status (DR1DRSSTZ, DR2DRSTZ )
The dietary recall status variable is used to indicate the quality and completeness of a survey participant’s response to the
dietary recall. This variable is important in identifying all individuals who should be included in a study. Four possible values
are provided. However, only two of the values (1 and 4) are included in Individual Foods File records.
The values for this variable are as follows:
1 = Reliable and met the minimum criteria. A value of 1 for this variable in the Total Nutrient Intakes File indicates that all
relevant variables associated with the 24-hour recall contain a value. Individuals who reported fasting are considered to have a
reliable recall.
2 = Not reliable or did not meet the minimum criteria. Data on individual food consumption are not provided for these cases.
These individuals do not have any valid records in the Individual Foods File nor do they have data on total nutrient intakes in
the Total Nutrient Intakes File. These records should not be included in nutrient intake estimates.
4 = Reported consuming breast milk. For breast-fed infants, the Individual Foods File includes a record for each report of
human milk. Because amounts of human milk are not quantified, these records contain missing values for the amount
consumed and for the amounts of energy and nutrients from human milk. Total nutrient intakes are not provided because of
this missing information. Breast-fed children are excluded from most analyses for the reasons stated above.
5 = Not done. This code is assigned when the dietary recall did not take place due to various reasons. These individuals have
no records in the Individual Foods File.
Breast-fed infant (either day) (DRABF )
Beginning with NHANES 2003-2004, the variable drabf is included to identify breast-fed children. This variable eliminates the
need to review and identify individuals with human milk records in the Individual Foods and Total Nutrient Intakes Files. This
variable has a code of 1 if a child consumed breast milk on either day of the recall.
Intake day of week (DR1DAY, DR2DAY )
This variable identifies the day that reported foods were consumed. By using this variable, intakes and eating patterns can be
compared according to day of week or by weekend days versus week days.
Food energy and nutrient variables (many)
Food energy and nutrient values in the Individual Foods File represent the amount of energy or nutrients provided by
consumed food. In the Total
Nutrient Intakes File, these values represent the total daily amount of nutrients consumed for each survey participant. These
totals were derived by summing the nutrient amounts from all foods listed in the Individual Foods File for a survey participant.
Variables in Individual Foods File only
Food/individual component number (DR1ILINE, DR2ILINE )
The Individual Foods File contains one record for each food consumed by a participant. Each food record is assigned a line
number. The dr1iline or dr2iline variable may be used along with the respondent sequence number to uniquely identify a food
record. An example is when a respondent reports the same food more than once in a day, as shown in the table below.
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SEQ N dr1iline Food
1
20000 2 Banana
20000 3 Milk
20000 4 Coffee
20000 Milk
USDA food code (dr1fdcd, dr2fdcd)
Every food in the Individual Foods File is identified by an 8-digit USDA food code. Each food code is associated with a food
description. There are two versions of each description: a complete, 200 character version and an abbreviated 60 character
version. Starting with the 2003-2004 release cycle, a Food Codes file that accompanies the Individual Foods File contains both
the long and short descriptions. An appendix in the file documentation provides SAS code to link the descriptions in the Food
Codes File with the USDA food code in the Individual Foods File.
Beginning with the 2001-2002 release, the source of the food codes is USDA’s Food and Nutrient Database for Dietary Studies
(FNDDS).
Modification code (DR1MC, DR2MC )
During the food coding process, predefined recipes for some food mixtures are modified to more closely match the food as
described by the respondent. Nutrients are modified by substituting ingredients in a predefined recipe for the mixtures. An
example of a modified recipe is an egg fried in butter instead of margarine. Each modification code is assigned a unique
6-digit identification number.
Beginning with the 2003-2004 release, the Modification Code file that accompanies the Individual Foods File includes
descriptions (up to 200 characters) associated with each modification code. An appendix contained in the file documentation
provides SAS code to link the descriptions in the Modifications Codes File with the modification code in the Individual Foods
File
Combination food number (DR1CCMNM, DR2CCMNM ) and combination food type ( DR1CCMTX,
DR2CCMTX )
The combination food number and combination food type variables can be important in planning analyses, especially when
accounting for mixed food items such as sandwiches, salads, or other mixed dishes or beverages. Some foods reported by
respondents are coded using more than one food variable, resulting in more than one record for the food. If a food is coded as
more than one item, it is called a combination. Combinations may represent one food added to another and consumed as a
unit, such as sugar added to coffee, margarine added to toast or gravy on potatoes, or components (ingredients) of foods, such
as sandwiches, salads, and mixed dishes.
All food records in a combination have the same values for the combination food number and combination food type variables
– the combination food number links a group of foods that are eaten together as a unit and the combination food type identifies
the type of combination.
Approximately 53% of all foods in the 2003-2004 dietary intake data were coded as combination type foods.
Combination food types assigned to codes for the 1999-2000 dietary data release cycle are not the same as
those for latter cycles. For example, a food code of “1” in the 1999-2000 dataset represents a baby food
combination; in the 2001-2002 and 2003-2004 datasets, “1” represents a beverage with additions.
Time of eating occasion (DR1_020, DR2_020 ) and name of eating occasion ( DR1_030Z, DR2_030Z )
Each food record includes the variables denoting time and name of eating occasion at which the food was consumed. Note that
the time of eating occasion variable is displayed in the 24-hour notation HH:MM. Additionally, codes assigned to the same
eating occasion may differ from one cycle to another.
The name of eating occasion variable may include more than one relevant code for the same eating occasion, due to the
inclusion of both English and Spanish terms. For example, three separate listings are provided for the breakfast eating
occasion—breakfast, desayuno, and almuerzo.
It may be useful to look at time of eating occasion when conducting an analysis because eating occasions may be reported at
any time of day. For example, the midday meal may be called lunch or dinner, and the evening meal may be called supper or
dinner.
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Extended consumption is used to denote the eating occasion when a respondent reports a food consumed over an extended
period of time without distinct periods of consumption.
Source of food (DR1FS, DR2FS )
The source of food variable identifies where a food was obtained, such as from a store, fast food restaurant, vending machine or
school cafeteria. This variable was first included with the 2003-2004 release.
Variables in Total Nutrient Intakes File only
Compare food consumed yesterday to usual (DR1_300, DR2_300 )
Each respondent was asked to assess whether the amount of food eaten on the recall day was usual, much more than usual, or
much less than usual.
Water intake variables (DR1_320, DR2_320, DR1_330, DR2_330, DR1BWATR, DR2BWATR, DR1CWATR,
DR2CWATR, DR1TWS, DR2TWS )
Data on intake of drinking water (i.e., tap water, plain bottled water, and unsweetened carbonated water) are generally
collected after the 24-hour dietary recall is completed. Drinking water data are collected during the 24-hour recall only when it
is an addition to other foods or is an ingredient in mixed beverages.
The availability of water variables varies with the release cycle. For the 2003-2004 release, four variables—plain, tap, bottled,
and carbonated—were included.
Special diet variables (DRQSDIET, DRQSDT1 – DRQSDT8, DRQSDT91 )
Beginning with the 2003-2004 release, information is included on whether the participant is currently on any kind of diet to
lose weight or for another health-related reason and if so, the type of diet. The variable drqsdiet identifies whether a
participant is on a special diet. The variables drqsdt1 through drqsdt8 and drqsdt91 identify the type of diet(s) the participant
follows. Responses to the type of diet were collected as “code all that apply,” meaning that more than one type of diet could be
reported.
Variables in both Individual Foods and Total Nutrient Intakes Files
Respondent sequence number (SEQN )
Each survey participant is identified by a 5-digit respondent sequence number. The seqn variable is present in most NHANES
files and can be used to link data from different files for a given respondent.
Number of days of intake (DRDINT )
Beginning with the 2003-2004 release, the variable drdint is included to indicate the number of days of intake available for
each participant. This variable eliminates the need to review records and identify individuals in the Individual Foods and Total
Nutrient Intakes Files with 1 or 2 days of intake.
Dietary Supplement Variables
Any dietary supplements taken (DSD010 )
This is a derived variable. Participants who took a product coded as a supplement in the past 30 days are coded as 1.
Supplements that were mistakenly recorded as an antacid in the medication section (RXQ) or as a prescription medication are
moved to the DSQ section and are counted as supplements. Participants who reported an antacid containing calcium or
magnesium in the past 30 days that was recorded only in RXQ antacid section and did not take any dietary supplement are
coded as 2. Participants who did not take any product determined to be a dietary supplement in the past 30 days are also coded
as 2. Prescription medicines and analgesics that are mistakenly recorded in the DSQ section are moved to their appropriate
sections for data release.
Total number of supplements taken (DSDCOUNT )
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This is the count given to all supplements reported in the dietary supplement (DSQ) or medications (RXQ) section, as well as
antacids that were reported in the DSQ section. Antacids recorded in the antacid section do not contribute to this count. Non-
supplements that were reported in the DSQ section do not count. Products with don’t know or refused responses, are counted
as supplements because no clear evidence exists that they are not and they were reported by the participant as a supplement.
Any non-prescription antacids taken (DSD010AN )
Indicates if any non-prescription antacids were taken.
Total number of non-prescription antacids taken (DSDANCNT)
Total number of non-prescription antacids taken per respondent.
Supplement ID Number (DSDSUPID)
These are numbers assigned by the database for each product entered. Supplement ID numbers are 10 digits long and all
Supplement IDs begin with the number ‘1’. The next 3 digits (positions 2-4) are ‘888’ if the supplement was created by NCHS as
a generic or default product; otherwise the digits in positions 2-4 are coded ‘000’. The next 4 digits (positions 5-8) are assigned
by the database and do not indicate anything about the product. The last 2 digits (positions 9-10) indicate formulations of the
same supplement: the first formulation entered into the database = 00, the first reformulation = 01, the next = 02, etc. Note
that these are reformulations of the same product: different versions (e.g. liquid vs. tablet, with iron vs. without iron, regular vs.
high potency) have different 4 digit numbers (positions 5-8). When a product name was entered as “refused” or “don’t know”,
the ID number is a string of 7’s or 9’s.
Name of Supplement (DSDSUPP)
This is the name from the supplement front label which is entered into the database. Matching what supplement the
interviewers record to an actual product label is made with varying degrees of certainty. When no match could be made, then
the product was given a match of 6, “unknown.” For these matches, the 10 digit supplement ID begins with a 6 and the phrase
“no product information” is assigned as the name. Products with brand names that are available only in a limited region of the
country are released with a generic name, not a brand name, to ensure participant confidentiality. Product names that were
entered as “refused” or “don’t know” are named “7777” and “9999”, respectively.
For some entries made by interviewers, no corresponding product label could be found nor could a reasonable default product
be assigned. These entries are counted as supplements because no evidence that they are not supplements, but only the words
“no product information available” are used in place of a name in this public data release.
Was container seen (DSD010)
This variable denotes whether the dietary supplement container was seen during the household interview. Containers are seen
approximately 88% of the time. This enables interviewers to collect more complete and accurate supplement names compared
to supplement containers that are not seen. For containers that are not seen, the interviewer relies on the participants’ memory
for the name of the supplement taken.
Matching code (DSDMTCH)
Supplements are recorded in the household interview with varying degrees of accuracy and completeness. The matching code
indicates the level of certainty with which a supplement recorded during the interview matches the actual supplement label.
How Long Supplement Taken (DSD090)
This variable is released in terms of days that a supplement has been taken by multiplying years by 365; months by 30.4; and
weeks by 7.
Days Supplement Taken, Past 30 Days (DSD103)
This variable is released as recorded by interviewer. This information is missing for dietary supplement data that were
recorded in the medication (RQX) section.
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Antacid reported as a dietary supplement (DSDANTA)
Indicates whether an antacid was reported in the dietary supplement (DSQ) or antacid section. For a few participants, the
same antacid was recorded in both questionnaire sections. In these instances, the antacid was considered to be in the DSQ
section and coded as 1.
Quantity and dosage form of supplement taken daily (DSD122Q)
This variable is released as recorded by interviewer. This information is missing for dietary supplement data that were
recorded in the medication (RXQ) section.
Supplement Information Source (DSDRCE)
The source of each product label is recorded in the database. These source codes are listed in Appendix 5 of the supplement file
documentation. Generic and default products do not have a source code.
Formulation Type (DSDTYPE)
The type of formula is recorded into the database. These codes are listed in Appendix 7 of the supplement file documentation.
Serving Size Quantity (DSDSERVQ)
This is thee product dosage quantity, which is recorded from the product label supplements facts panel. When calculating the
amount of a nutrient consumed from supplements, it is important to take serving size into consideration. For some
supplements, the serving size may be more than one unit (e.g., tablet, drop, teaspoon). In addition, the ingredient listed may be
a compound (e.g. calcium carbonate), and the amount of the elemental nutrient (e.g., calcium) needs to be calculated.
Appendix 5 of the supplement file documentation contains suggestions for conversions, but analysts are advised to confirm
these.
Serving Size Unit (DSDSERVU)
This is the serving size unit, which is recorded from the product label supplements facts panel. The codes are listed in
Appendix 10 of the supplement file documentation.
Alternative Serving Size (DSDSERVA)
This is listed in labels for some products. Not all products offer an alternative serving size.
Label may include alternative serving size (e.g., 1 dropperful = 1 mL).
Ingredient ID (SDSDINGID)
This is the ingredient ID created by the NCHS database for each ingredient recorded from the product label supplements facts
panel.
Ingredient name (DSDINGR)
Ingredient names are recorded from the product label supplements facts panel.
Ingredient operator (DSDOPER)
This is a symbol (=, < , or >) that comes from the product label supplements facts panel.
Ingredient quantity (DSDQTY)
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Ingredient quantity is recorded for each ingredient listed from the product label supplements facts panel.
Ingredient unit (DSDUNIT)
Ingredient unit is recorded for each ingredient listed from the product label supplements facts panel. Appendix 11 of the
supplement file documentation lists the code for these.
Ingredient category (DSSDCAT)
NCHS assigns ingredient categories: Vitamin, Mineral, Botanical, Others, Amino Acid. Appendix 8 of the supplement file
documentation lists the code for these variables.
Number of ingredient categories in each supplement (DSDCNT)
For each supplement, this variable is the number (count) of ingredients in each ingredient category (vitamin, mineral, amino
acid, botanical, other) listed in the facts box on the label, including ingredients listed within blends.
Number of vitamins in the product (DSDCNTV)
Number of minerals in the product (DSDCNTMdsdcntm)
Number of amino acids in the product (DSDCNTA)
Number of botanicals in the product (DSDCNTB)
Number of other ingredients in the product (DSDCNTO)
Blend Flag (DSDBLFLAG)
This indicator variable denotes whether an ingredient is a blend or not a blend.
Blend component ID (DSDBCLID)
These are ingredient ID numbers for blend ingredients.
Blend component name (DSDBCNAM)
These variables are the ingredient names for blend ingredients. Blends in products will not give the actual breakdown of
ingredient quantities in the blend. The ingredients will usually just be listed, and most of the time a whole blend amount is
given.
NCHS assigns ingredient categories for each blend ingredient: Vitamin, Mineral, Botanical, Others, Amino Acid. Appendix 8 of
the supplement file documentation lists the code for these variables.
Page last updated: May 3, 2013
Page last reviewed: November 10, 200 9
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
6 of 6 1/14/2019, 9:32 PM
NHANES Dietary Web Tutorial - Technical & Software Requirements https://www.cdc.gov/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm
Technical and Software Requirements
To view the tutorial, you will need the following:
an Internet browser configured to allow pop-up windows (#popup) ;
an Internet browser configured to allow blocked content to run (#blocked) ;
a monitor resolution of at least 800x600 pixels (#settings) and text size that is easy for you to read (#settings) ;
Adobe Acrobat Reader (#reader) ; and
Adobe Flash 8 player (#flash) .
In addition, a software license to run SAS and/or SUDAAN (#statistic_sw) is very helpful, though not required.
Allowing pop-up windows
Any of the more recent Netscape, Internet Explorer, and Firefox browsers should run the JavaScript code to produce pop-up
windows. However, the security settings on your browser may block the pop-up windows from opening.
This tutorial makes heavy use of pop-up windows. Pop-up windows make it easier for you to access additional information if
you want it, and to return to the main page of each module without having to use the browser's Back button.
How to allow pop-up windows (howtoallowpopupwindows.htm)
Allowing blocked content to run
The NHANES web tutorial also uses scripting to make its contents interactive. Microsoft Internet Explorer may be configured
to block this content.
How to allow blocked content to run (howtoallowactivecontenttorun.htm)
Setting your monitor's resolution and adjusting your text size
The CDC website is 800 pixels wide. Therefore, a monitor resolution of 800x600 pixels is the minimum you should use. If you
use a narrower width resolution, you will have to scroll side to side, as well as up and down. We recommend a 1024 X 780
resolution for optimal viewing.
How to set your monitor’s resolution and ad just your text size (howtomonitorres_textsize.htm)
Getting Adobe Acrobat Reader
All NHANES documentation is in Acrobat .PDF format. You will need the Reader to view and read the documentation that
accompanies the data files.
You can download the free Adobe Acrobat Reader from Adobe's website at http://www.adobe.com/products/acrobat
/readstep2.html (http://www.adobe.com/products/acrobat/readstep2.html) .
Installing a Flash Player
All of the tutorial animations are in Flash .SWF format. To view them you will need a Flash Player. However, you do not have to
view the animations to complete the tutorial.
How to install a Flash Player (howtoinstallflashplayer.htm)
Obtaining SAS and SUDAAN
Many tutorial modules contain sample code. If you wish to run this code on your own, you must have a software license to run
SAS and/or SUDAAN on your computer.
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How to obtain SAS and SUDAAN (howtoobtainsas_sudaan.htm)
IMPORTANT NOTE
To report problems or send comments, use the NHANES Web Tutorial email (mailto:[email protected]) . Do not direct
questions to this email address. You will NOT receive a reply. This email address can be used only for sending
feedback to the Web Tutorial Team.
Page last updated: May 2, 2013
Page last reviewed: May 2, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
2 of 2 1/14/2019, 9:32 PM
NHANES Dietary Web Data Tutorial - Advanced Dietary Analyses https://www.cdc.gov/nchs/tutorials/dietary/AdditionalResources/links.htm
Links
Disclaimer
The following links may be helpful as a complement to the NHANES Dietary Web Tutorial. Please note that references on these
sites to any specific commercial products, process, service, manufacturer, or company do not constitute an endorsement or
recommendation by the U.S. Government or CDC. CDC is not responsible for the content of any "off-site" Web page and does
not take any ownership of the content found on external non-federal Web sites that link back to the CDC. Information or
services detailed on external sites are not endorsed, warranted or guaranteed and are not necessarily representative of the
views of CDC or the U.S. Department of Health and Human Service.
National Cancer Institute Links
Usual Dietary Intakes: Background
http://riskfactor.cancer.gov/diet/usualintakes/ (http://riskfactor.cancer.gov/diet/usualintakes/)
This page provides the rationale for using statistical methods to estimate usual intakes.
Usual Dietary Intakes: The NCI Method
http://riskfactor.cancer.gov/diet/usualintakes/method.html (http://riskfactor.cancer.gov/diet/usualintakes/method.html)
This page summarizes the NCI method for estimating usual intake of nutrients and foods and provides answers to frequently
asked questions about the method.
Usual Dietary Intakes: Details of the Method
http://riskfactor.cancer.gov/diet/usualintakes/details.html (http://riskfactor.cancer.gov/diet/usualintakes/details.html)
This page outlines the NCI approach to estimating usual intakes in further detail.
Usual Dietary Intakes: Food Intakes, US Population, 2001-04
http://riskfactor.cancer.gov/diet/usualintakes/pop/ (http://riskfactor.cancer.gov/diet/usualintakes/pop/)
This series of tables provides the first ever estimates of distributions of food intake for the US population, for a wide range of
food groups.
Usual Dietary Intakes: SAS Macros for Running the NCI Method
http://riskfactor.cancer.gov/diet/usualintakes/macros.html (http://riskfactor.cancer.gov/diet/usualintakes/macros.html)
To help analysts get started, this page contains sample programs and macros for analysis of data, including those from the
NHANES, and an associated users guide.
U.S. Department of Agriculture Links
Food and Nutrient Database for Dietary Studies (FNDDS)
http://www.ars.usda.gov/services/docs.htm?docid=7673 (http://www.ars.usda.gov/services/docs.htm?docid=7673)
The FNDDS is a database of foods, their nutrient values, and their weights for typical food portions. The components of the
FNDDS are used to process and analyze NHANES dietary recall data.
My Pyramid Equivalents Database
http://www.ars.usda.gov/Services/docs.htm?docid=17558 (http://www.ars.usda.gov/Services/docs.htm?docid=17558)
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The MyPyramid Equivalents Database (MPED) is a tool to help researchers examine dietary recall data in terms of MyPyramid-
defined food groups and portion units.
USDA Food Coding Scheme
http://www.cdc.gov/nchs/tutorials/Dietary/SurveyOrientation/ResourceDietaryAnalysis/frame2.htm (/nchs/tutorials/Dietary
/SurveyOrientation/ResourceDietaryAnalysis/frame2.htm)
The USDA food coding scheme is a way of organizing the thousands of food codes used in NHANES and can be used as a guide
to grouping foods for your particular research needs.
What’s in the Foods You Eat Search Tool
http://www.ars.usda.gov/Services/docs.htm?docid=17032 (http://www.ars.usda.gov/Services/docs.htm?docid=17032)
The USDA’s What's in the Foods You Eat is a tool allows you to easily search the FNDDS.
Other Links
Choosing the correct analysis
http://www.ats.ucla.edu/stat/mult_pkg/whatstat/default.htm (http://www.ats.ucla.edu/stat/mult_pkg/whatstat/default.htm)
The table shows general guidelines for choosing a statistical analysis for various survey designs and in Stata, SAS, and SPSS.
Summary of Survey Analysis Software
http://www.hcp.med.harvard.edu/statistics/survey-soft/ (http://www.hcp.med.harvard.edu/statistics/survey-soft/)
This page is a summary of available software for the analysis of surveys with complex sample designs and a references to review
articles with links to on-line articles.
Page last updated: November 10, 2009
Page last reviewed: November 10, 2009
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
2 of 2 1/14/2019, 9:32 PM
NOTES
UNIT 1
DIETARY DATA SURVEY
ORIENTATION
NOTES
NHANES Dietary Web Tutorial - Survey Orientation https://www.cdc.gov/nchs/tutorials/dietary/SurveyOrientation/intro.htm
Dietary Data Survey Orientation
The Survey Orientation course includes five modules:
Module 1. Dietary Data Overview (/nchs/tutorials/Dietary/SurveyOrientation/DietaryDataOverview/intro.htm)
Module 2. Navigate NHANES Website (/nchs/tutorials/Dietary/SurveyOrientation/Navigate/intro.htm)
Module 3. Dietary Data Structure & Contents (/nchs/tutorials/Dietary/SurveyOrientation/DietaryDataStructureContents
/intro.htm)
Module 4. Resources for Dietary Data Analysis (/nchs/tutorials/Dietary/SurveyOrientation/ResourceDietaryAnalysis
/intro.htm)
Module 5. Overview of NHANES Survey Design and Weighting (/nchs/tutorials/Dietary/SurveyOrientation
/SurveyDesign/intro.htm)
These five modules provide a general overview of the dietary data collected by the NHANES, the NHANES website, the
structure and contents of NHANES dietary data, additional databases and tools that can be used to conduct dietary analyses,
and the NHANES survey design and weighting principles. A vast amount of dietary data are organized and released in separate
data files on the NHANES and USDA websites. These data files are organized according to certain conventions. Moreover,
NHANES uses a complex sampling design with sample weights to ensure that the data are nationally representative. Therefore,
a thorough understanding of the material covered in these modules will help you be more efficient in finding the information
you need for your analysis.
Whether you are a novice or an experienced analyst, it isrecommend that you review this entire course (Modules 1-5)
before proceeding with the rest of the tutorial, as these five modules serve as a roadmap that will help you get oriented quickly
or refresh your knowledge of NHANES in general and its dietary data in particular.
Users who wish to pick and choose topics of interest in this course or throughout the tutorial may do so by using the navigation
bar to the left or by using the Tutorial A-Z Index (/nchs/tutorials/dietary/a-zindex.htm) .
The course begins with a Dietary Data Overview, where you will learn about the history and methodology of dietary data in
NHANES as well as some of the ways in which these data are used. In the next module, Navigate the NHANES Website, you
will learn where to find different documents, how to access datasets, and how to get help with NHANES data. The third
module, Data Structure & Contents, will show you how the dietary data are organized. Resources for Dietary Data Analysis
describes additional sources of food and nutrient data and provides web addresses for accessing these resources on the USDA
website. These data are often used in dietary analyses. Finally, Overview of NHANES Survey Design and Weighting describes
the complex sampling design of NHANES and explains why and how NHANES sample weights are constructed.
Before you get started:
Check out the Dietary Data Tutorial Roadmap (/nchs/tutorials/Dietary/roadmap.htm) to orient yourself to the tutorial’s
content.
Read the Introduction (/nchs/tutorials/Dietary/introduction.htm) to find answers to frequently asked questions about
NHANES dietary data and this tutorial.
Browse through the Logistics (/nchs/tutorials/dietary/logistics/logistics.htm) section to learn about the web layouts and
templates used in the tutorial and find out the basic knowledge and skills you’ll need to use the tutorial.
Go to Technical & Software Requirements (/nchs/tutorials/dietary/logistics/techsoftwarereqs.htm) for information about
what’s required to view the tutorials correctly and run the sample programs properly. This section also is the place to go
if you need help with technical problems.
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
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NHANES Dietary Web Tutorial - Dietary Data Overview https://www.cdc.gov/nchs/tutorials/dietary/SurveyOrientation/DietaryDa...
Dietary Data Overview
Purpose
This module provides an overview of the dietary data in the National Health and Nutrition Examination Surveys (NHANES) by
briefly describing the history of national dietary surveillance, the methodology for collecting dietary data, and uses of these
data.
Task 1: Describe the History of Dietary Data Collection
For many decades, the U.S. Department of Health and Human Services (HHS) and the U.S. Department of Agriculture (USDA)
each collected dietary data using a variety of methodologies, including in-person and telephone interviews and self-
administered surveys. In 2002, USDA and HHS integrated their dietary recall data collection efforts into the current NHANES.
In addition to the 24-hour dietary recall data, NHANES collects other information on dietary behaviors, including supplement
usage and frequency of food consumption, as well as a range of health measures and sociodemographics. These data respond
to a variety of public health and research priorities.
Key Concepts about the History of Dietary Data Collection (/nchs/tutorials/Dietary/SurveyOrientation/DietaryDataOverview
/Info1.htm)
Task 2: Describe NHANES Dietary Collection Methods
NHANES collects dietary data through interviews, physical examinations, and post-examination interviews and
questionnaires. Dietary data collection is integrated into these data collection modes, which include 24-hour recalls, food
frequency questionnaires, and survey questionnaires.
Key Concepts about NHANES Dietary Data Collection Methods (/nchs/tutorials/Dietary/SurveyOrientation
/DietaryDataOverview/Info2.htm)
Task 3: Describe Uses of the Dietary Data
HHS, USDA, other federal agencies, and a wide range of researchers are major users of NHANES dietary data. These data have
been central to the formulation of public health policy and practice.
Key Concepts about Uses of the Dietary Data (/nchs/tutorials/Dietary/SurveyOrientation/DietaryDataOverview/Info3.htm)
IMPORTANT NOTE
For an overview of the history, methodology of, and uses of the overall NHANES, visit the Continuous NHANES Web Tutorial
(/nchs/tutorials/Nhanes/SurveyOrientation/SurveyOverview/intro.htm) .
Page last updated: May 3, 2013
Page last reviewed: May 3, 2013
Content source: CDC/National Center for Health Statistics
Page maintained by: NCHS/NHANES
Centers for Disease Control and Prevention 1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
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