By Jonathan W. King, Ph.D.
The National Institute on Aging (NIA) received $275 million in funding over two years through the American Recovery and Reinvestment Act (ARRA). Largely, these funds—received through a series of grants and initiatives—helped intensify and expand scientific study of conditions such as Alzheimer’s disease and support the research infrastructure around aging and age-related cognitive change.
Among the many important projects NIA supported using ARRA funds was the genotyping of DNA samples collected from almost 20,000 participants in the Health and Retirement Study (HRS). Many of you will be familiar with the HRS—a nationally representative longitudinal panel study that collects data from 20,000 Americans ages 50 and older every 2 years, with the goal of exploring changes in health, wealth, and well-being. Its unique sampling frame makes it especially valuable when nationally representative samples are needed. In 2007, HRS data played a crucial role in helping to estimate dementia prevalence in the United States; in 2013, the study provided the key data that confirmed the enormous monetary costs of dementia in the country.
Wide Participation and Quality Publications
Although the HRS was not the only cohort study to benefit from ARRA funds, it has turned out to be an especially important one, granting us the best picture we have of genetic diversity among older adults in the United States. HRS genomic and phenotype data have been included in more than 200 genome-wide association studies in 39 different projects and as a partner in six different consortia. Initially, many of the papers using HRS genomic data focused on biomedical and disease phenotypes; more recently, however, the data have been used to answer behavioral and social science research questions. One study relying on HRS data suggests that married couples are more genetically similar than chance would allow.
Papers using these data have appeared in several leading journals, including Nature, Nature Genetics, Science, and PNAS. Dozens of additional papers are in the works from the 152 research groups that have sought and received approval to download and use the data from dbGaP.
More Data Will Be Available Soon
As of today, data from only 12,507 participants are available on dbGaP. We anticipate that the completed sample of 18,764 unrelated individuals will be available in the first half of 2016. Particularly important in this full dataset is the genotype information from more than 6,000 HRS participants who are racial and ethnic minorities, including more than 3,000 African American participants. Indeed, it was the presence of rich racial and ethnic diversity in the cohort that drove the decision to genotype (at significantly higher cost) on the (then) densest genotyping array available (Illumina Omni2.5), yielding more than 2 million single nucleotide polymorphisms (SNPs) per individual; these 2 million SNPs in turn have been used to impute 79 million variants using the 1000 Genomes Phase 3 reference panel. That’s 79 million possibilities just waiting for a question to be asked.
Of course, not every research question requires quite that much data, and the HRS also provides a range of genomic products, including data better suited for candidate gene analyses and (in the near future) the full genetic relatedness matrix for HRS participants and polygenic risk scores obtained from genome-wide association studies for a variety of traits.
With such an abundance of phenotype and genotype data, it can be difficult to know where to start, but now that you know more about what is available, please feel free to send us an email and let us help you get started.
Originally posted at Inside NIA: A Blog for Researchers
About the Author
Jonathan W. King, Ph.D.
Jonathan W. King, Program Director Division of Behavioral and Social Research, National Institute on Aging, received his Ph.D. in Cognitive Psychology from Carnegie Mellon University. His post-doctoral work in cognitive neuroscience at the Department of Cognitive Science at the University of California, San Diego, focused on language processing and working memory in both younger and older adults. Dr. King later joined the faculty in the Department of Psychological Sciences and the Interdisciplinary Neuroscience Program at the University of Missouri-Columbia. He joined the Biobehavioral and Behavioral Processes Integrated Review Group at the Center for Scientific Review at the NIH in 2006 and is currently working as the program director for Cognitive Aging and Human Factors in the Division of Behavioral and Social Research (BSR) at the NIA. While at the BSR, he has coordinated new initiatives in cognitive interventions to remediate age-related cognitive decline and the use of behavioral economic approaches both to promote health behavior change in older adults and to increase the uptake of comparative effectiveness research. Dr. King is also the roadmap coordinator for the NIH Science of Behavior Change Roadmap Project effort.
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