At a glance
- Learn what restricted data are available from the National Health and Nutrition Examination Survey.
- Researchers interested in using these data must obtain approval through the Research Data Center.
Overview
The National Health and Nutrition Examination Survey (NHANES) collects data on the health and nutritional status of adults and children in the United Status. The survey combines interviews and health examinations. NHANES is conducted by the National Center for Health Statistics (NCHS).
Data
NCHS restricts access to variables such as geographic details, dates, and genetic data, and provides guidelines for access and usage for restricted data.
Geographic variables
NCHS restricts access to geographic detail below the national level for continuous NHANES (starting with the 1999-2000 cycle). For cycles prior to 1999, access to geographic detail below the regional level is restricted.
Dates
NCHS restricts the exact date of interview and exam for all years. NHANES does not provide a variable name for exact date of interview and exam in the limited access documentation.
In your proposal and data dictionary use DATE as the variable name. In the description portion, describe the date (i.e., exact date of interview).
- Exact interview date
- Exact date of examination
Genetic data
DNA specimens were collected in the NHANES III (1988–1994) and in subsequent NHANES cycles (1999–2002, 2007–2008, 2009–2010, and 2011–2012).
Please direct your questions about genetic data to NHANESGenetics@CDC.gov and about the Research Data Center (RDC) process to RDCA@cdc.gov.
Limited access data
Continuous NHANES variable search tool
- Enter the keywords to search for specific variables. Select "Include" or "Only" from the drop-down menu for "Limited Access."
- Select the survey cycle(s) of interest, then select "Limited Access Data" under the "Data, Documentation, Codebooks, SAS Code" section.
Linked data
NCHS links NHANES data with various other types of data, including—
- Mortality
- Medicare claims
- Social Security benefits
- Air quality data
- Quarterly Food-at-Home Price Database (QFAHPD)
Quarterly Food-At-Home Price Database
NCHS conducted a data linkage of the NHANES to the Quarterly Food-At-Home Price Database from U.S. Department of Agriculture's Economic Research Service.
The NHANES linked food price data files include the continuous NHANES years (1999–2006). Linkage of the NHANES survey participants with the QFAHPD supports research on the economic determinants of—
- Food consumption
- Diet quality
- Health outcomes
These data files contain geography-specific information, therefore, are not available for public use.