National Health and Nutrition Examination Survey (NHANES) Restricted Variables

Geographic Variables

All geography below the national level is restricted for continuous NHANES, prior to that all geography below the regional level is restricted.



The exact date of interview and exam are restricted 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 and in the description portion, describe the date (i.e exact date of interview).

Variable Name Variable Description
Intvw DATE Exact Interview Date
Exam DATE Exact Date of Examination

Genetic Data

DNA specimens were collected in the National Health and Nutrition Examination Survey (NHANES) III (1988–1994) and in subsequent NHANES cycles (1999–2002, 2007–2008, 2009–2010, and 2011–2012).

More Information about Genetic Data

Please direct your questions about genetic data to, and the RDC process to


Limited Access Data from NHANES

Continuous NHANES variable search tool.

Enter the keywords to search for specific variables. Select “Yes” on the Include Non–public Variables line.

Search by a survey cycle

Select the survey cycle(s) of interest and determine what restricted variables are available. This is the only way to identify restricted variables for NHANES II and NHANES III.


Linked Data Products

NHANES has been linked to Mortality, Medicare Claims, Social Security Benefits, and Air Quality data.


Quarterly Food–at–Home Price Database

NCHS has conducted a data linkage of the National Health and Nutrition Examination Survey (NHANES) to the Quarterly Food–at–Home Price Database (QFAHPD) from USDA’s Economic Research Service (ERS). The NHANES Linked food price data files include the continuous NHANES years (1999–2006). Linkage of the NHANES survey participants with the QFAHPD provides the opportunity to support research on the economic determinants of food consumption, diet quality, and health outcomes. These data files contain geography–specific information, therefore, are not available for public–use.

Page last reviewed: May 11, 2018