The Age, Gene/Environment Susceptibility (AGES) -Reykjavik Study was initiated to examine potential genetic susceptibility and gene/environment interaction as these contribute to disease, disability, and risk of death. The study is based on the premise that many conditions in old age, such as cardiovascular disease, osteoporosis, and Alzheimer's disease, may share common pathophysiologic mechanisms such as inflammation and glucose dysregulation, and that common genetic factors underlie these mechanisms. Understanding the genetic contribution to chronic diseases of old age could create novel interventions to prevent disease and limit disability.