In 1967, all 30,795 men and women living in the capital area of Iceland and born between 1907 and 1935 were invited by the Icelandic Heart Association to join a prospective cohort study. Approximately 19,000 attended the clinic at least once and became participants of the Reykjavik Study. Subsequently, in 2002, a random sample of the cohort comprising 5,764 men and women who were still alive in Iceland and aged 66 to 96 years entered the Ages Gene/Environment Susceptibility (AGES) - Reykjavik Study