The Incidence Study— Study Design and Methods

Abstract

A biracial sample of 3,102 persons from Evans County, Georgia, was first examined in 1960-1962. Of this original cohort 2,530 persons were reexamined in 1967-1969. From these two observations the incidence rates for the 87-month period of both coronary heart disease and stroke were determined. The recent examination procedure included a complete medical history and physical examination, with a detailed questionnaire for evidence of cerebrovascular disease and symptoms of transient cerebral ischemia, an electrocardiogram, chest x-ray film, laboratory procedures, and sociological and physical activity questionnaires. Between 1960 and 1962 a study of the prevalence of coronary heart disease was conducted in Evans County, Georgia.¹ For this purpose 100% of the population aged 40 years and older and a 50% random sample of those 15 to 39 years were invited to undergo a complete medical examination. Cooperation was obtained from 3,102 individuals, representing 92% of those eligible for examination. Beginning