The Normative Aging Study (NAS) is a longitudinal study established by the United States Department of Veterans Affairs in 1963. Participants were male residents and free of chronic disease at the time of recruitment. Participants were invited to undergo an in-person examination every 3-5 years. Participants provided information on medical history, lifestyle and demographic factors and underwent a physical examination and laboratory tests, at each visit. Participants provided written informed consent at each visit, and the VA Boston Healthcare System Institutional Review Board approved the study.

The Normative Aging Study (NAS) is a longitudinal study established by the United States Department of Veterans Affairs in 1963. Participants were male residents and free of chronic disease at the time of recruitment. Participants were invited to undergo an in-person examination every 3-5 years. Participants provided information on medical history, lifestyle and demographic factors and underwent a physical examination and laboratory tests, at each visit. Participants provided written informed consent at each visit, and the VA Boston Healthcare System Institutional Review Board approved the study.