DNA Specimens and 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). The program is a nationally representative collection of stored DNA specimens and genetic data and will serve to add to the extensive amount of health, nutritional, and environmental information collected from NHANES.
DNA was extracted from crude lysates of cell lines created from blood of participants aged 12 years and over. For NHANES III Phase II (1991-1994), DNA concentrations per specimen vary and are estimated to range from 7.5-65 nanograms of DNA per microliter with an average of approximately four micrograms of DNA in 100 µl.
NHANES 1999-2002, 2007-2012
DNA was purified from whole blood of participants aged 20 years and over. Aliquots of purified DNA were normalized to concentrations of approximately 50 nanograms of DNA per microliter.
|Cycle||Age (years)||Types of Specimens||N|
|NHANES III Phase II||12+||DNA from crude cell lysates||7,159|
|1999-2002||20+||DNA from blood samples||7,839|
|2007-2008||20+||DNA from blood samples||4,615|
|2009-2010||20+||DNA from blood samples||3,898|
|2011-2012||20+||DNA from blood samples||~3,800|
Resulting genetic variants are deposited into the NHANES Genetic Data Repository after NCHS Quality Control Review. The majority of the datasets will be found in the category of restricted datasets although there are a small number of anonymized datasets.
For information about NHANES genetic datasets and weights review the Genetic Data Repository Information Sheet [PDF - 35 KB] and Weights Documentation [PDF - 35 KB].
Accessing the list of genetic variants is available via the NHANES Genetic Variant Search. For written instructions and additional information review the Genetic Variant Search Information Sheet [PDF-29 KB].
Questions: Email NHANESGenetics@cdc.gov.
Anonymized Genetic Datasets
A limited number of associated variants have been anonymized so the data can no longer be linked to the public use files and therefore not linkable to other NHANES data. Data available upon request with a data use agreement. List of anonymized datasets [PDF-63 KB]. Contact NHANESGenetics@cdc.gov for more information.
Quality Control Review
Only variants that pass NCHS Quality Control Review are added to the Genetic Data Repository. Documentation of NCHS Quality Control Review procedures: For candidate gene studies [PDF-82 KB]
DNA specimens are available for NHANES III, 1999-2000, 2007-08, and 2009-10. For additional information and proposal guidelines, please see the Federal Register.
Access the Genetic Data Repository
Proposals to analyze genetic datasets may be submitted to the Research Data Center (RDC). For additional information on submission guidelines, please go to the RDC website. Contact NHANESGenetics@cdc.gov for more information.
Publications Using DNA Specimens
Frequently Asked Questions
What kind of studies can I do with the NHANES DNA specimens?
NHANES is a nationally representative study and DNA specimens are best utilized to determine associations with diseases or conditions using the survey sample weights. Case-control studies are discouraged.
What are the proposal guidelines for accessing the Genetic Data Repository?
- Page last reviewed: January 18, 2017
- Page last updated: January 18, 2017
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