The Evans County Studies were initiated as a result of a request from the National Heart Institute in the late 1950's to develop epidemiological studies in areas where significant racial or ethnic differences in cardiovascular disease rates had been observed and where a stable population was available for long-term follow-up. Evans County was in a region of the United States known, at the time, to have the highest total death rates for all causes, of which coronary heart disease and hypertension were major contributors. At that time, Black males and females were known to have four times less coronary heart disease than white males, showed no sex differences for coronary heart disease mortality, and consumed more animal fat and had 50 percent more hypertension.