At a glance
- The National Health and Nutrition Examination Survey (NHANES) collected DNA specimen data in various survey cycles from 1988–2012.
- The majority of resulting datasets are restricted and only available to approved researchers.
- Explore the various genetic datasets and procedures for accessing them.
Introduction
The National Health and Nutrition Examination Survey (NHANES) biospecimen program provides a nationally representative collection of stored DNA samples and genetic data. The program adds to the extensive amount of health, nutritional, and environmental information provided by NHANES.
NHANES has processed participant blood samples to produce DNA concentrates from—
- NHANES III (1988–1994)
- NHANES 1999–2002
- NHANES 2007–2008
- NHANES 2009–2010
- NHANES 2011–2012
Laboratory methods
| Cycle | Age (years) | DNA Source | N |
|---|---|---|---|
| NHANES III Phase II | 12+ | crude cell lysates | 7,159 |
| 1999-2002 | 20+ | whole blood | 7,839 |
| 2007-2008 | 20+ | whole blood | 4,612 |
| 2009-2010 | 20+ | whole blood | 4,893 |
| 2011-2012 | 20+ | whole blood | 4,147 |
NHANES III
Laboratory professionals extracted DNA crude lysates of cell lines created from blood samples from participants ages 12 years and older. For NHANES III Phase II (1991–1994), DNA concentrations per specimen vary. Estimated concentrations range from 7.5–65 nanograms of DNA per microliter. This shows an average of approximately 4 micrograms of DNA in 100 microliters.
More recent cycles
Laboratory professionals purified DNA whole blood specimens from participants ages 20 years and older. Specimens of purified DNA were normalized to concentrations of approximately 50 nanograms of DNA per microliter.
Genetic Data Repository
After the National Center for Health Statistics (NCHS) performs a quality control review, the resulting genetic data for variants are deposited into the NHANES Genetic Data Repository. We only add variant data that pass the NCHS quality review to the Genetic Data Repository.
NCHS restricts access to most of these datasets. A small number of anonymized datasets are available for approved proposals through a data use agreement.
Restricted datasets
Genetic datasets and weights
List of genetic variants
Anonymized genetic datasets
NCHS has anonymized a limited number of associated variants. The data can no longer be linked to the public use files. Therefore, they are not linkable to other NHANES data.
These data are available upon request with a data use agreement.
Research proposals
NHANES is a nationally representative survey. Researchers can use results from analyses of DNA specimens to determine associations with diseases or conditions. We discourage use of these specimens for case-control studies.
Proposal guidelines
Find proposal requirements and submission procedures for requesting access to DNA specimens in the Federal Register.
Submit proposals to analyze restricted genetic datasets to the NCHS Research Data Center (RDC). Find submission guidelines on the RDC website.
Cost
There is a fee associated with using NHANES DNA specimens. The fee covers the cost of processing and shipping the samples.
We publish updates to the cost structure in the Federal Register Notice. Researchers should check the most recent notice to find current cost information.
Approval process
The NHANES Project Officer and a technical panel evaluate all proposals for scientific merit. These reviewers also confirm that the research will not produce results of clinical significance to the NHANES participant. Find the definition of clinical significance in the Federal Register Notice.
The NCHS Human Subjects Contact, Confidentiality Officer, and Ethics Review Board then review each proposal. They are responsible for identifying any potential human subjects or confidentiality concerns.
NCHS has published the technical evaluation criteria for these reviews in the Federal Register.
After approval
Researchers must sign an interagency agreement or a materials transfer agreement with NCHS after their proposals are approved.
Once the formal agreement is signed, the NHANES Project Officer will contact the researcher to arrange the transfer of specimens. Researchers must provide payment before specimens are released.
Progress reports
Researchers must submit a progress report each year of the research project. These reports should show progress year over year. If work continues beyond five years, researchers must provide an updated project timeline to complete the study.