When the study began in 1948, about 10,000 of Framingham's 28,000 residents fell within the study's preferred age range of 30 to 62 years (the age group shown to precede that at risk of developing heart disease). From this group, 5,209 men and women agreed to physical exams every two years for the next 20 years. Of these, 5,127 were free of coronary heart disease at the start of the study. At each biennial exam, in addition to a basic heart check-up, the researchers performed a special study. For instance, at Exam 4, the degree of obesity was determined; at Exam 11, fasting lipids were measured.
In 1971, the children of the original cohort, as well as their spouses, were asked to participate in a new heart study. The Offspring Study included 5,135 participants, aged 20 to 70. According to William B. Kannel, former study director, the Offspring Study was ...
