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National Health and Nutrition Examination Survey (NHANES) Restricted Variables

We encourage researchers to review guidelines and information on NHANES sample design and analytic guidelines before submitting proposals.


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


Genetic Data

The genetic data collected by NHANES is largely restricted.

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


Limited Access Data from Continuous NHANES


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. They can be accessed through the NCHS Research Data Center (RDC).