Task 1: Key Concepts About How Dietary Data Fit Into the NHANES Data Structure

 

Cycles

The Continuous NHANES data are released in two-year cycles beginning with NHANES 1999-2000 (See the "Overview of NHANES Survey Design and Weights" module for information about the reasons for this policy.)  Some survey topics areas are included in all survey cycles, whereas others are included in selected cycles.

 

Sections

The data for each survey cycle are composed of five sections:  Demographics, Dietary, Examination, Laboratory, and Questionnaire. 

Each section contains groups of related variables, packaged in one or more data files for each 2-year cycle.  This organization scheme allows for efficiency in posting data to the website, downloading them, and analyzing them. 

For each cycle of the continuous NHANES, the 1999-2010 Survey Content Brochure provides:

The following table lists examples of the diet-related survey data files and topics that were included in NHANES 2003-2004.   

 

Diet-Related Survey Components in NHANES 2003-2004
Section Data Topics Data Collection Setting
Examination
  • Dietary recalls (4 data files)
  • Body composition
  • Body measurements
  • Blood pressure examination
  • Physical activity monitor
  • Cardiovascular fitness
  • Mobile Examination Center (MEC) (first dietary recall)
  • Telephone follow-up (second dietary recall)
Laboratory
  • Serum cholesterol and lipoproteins
  • Serum and red blood cell folate
  • Iron status and hematology
  • Other nutritional biochemistry data
  • MEC
Questionnaire
  • Blood pressure
  • Cardiovascular disease
  • Current health status (self-reported)
  • Diabetes
  • Dietary supplements (5 data files)
  • Medical conditions
  • School meal program participation
  • Food stamp program participation
  • Household (HH) interview
  • Fish & shellfish consumption
  • Table salt use

  • MEC dietary interview (Day 1)
  • Plain water intake
  • Dietary interviews (Days 1 and 2)
  • Alcohol use
  • Reproductive health (including breast feeding)
  • Self-reported pregnancy status
  • MEC private interview
  • Weight history
  • WIC participation
  • HH and MEC private interviews
  • Food Frequency Questionnaire (2 data files)
  • Post-exam mailed questionnaire
  • Special diets
  • HH and post-MEC phone interviews
  • Food security
  • HH and MEC interviews

 

info iconIMPORTANT NOTE

This NHANES diet tutorial focuses primarily on dietary recall data, dietary supplement data, and food frequency data.  However, the principles described and analyses demonstrated in the tutorial also apply to the other types of dietary data collected in NHANES.

 

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