Using data supplied by the Social Security Administration, the vital status of the MRFIT screenees was determined. A screenee was identified as deceased if the social security number and first two letters of the last name, as recorded on the MRFIT screening form, matched a record on the Social Security Administration master death file. The state health department was contacted to obtain the death certificate which was then coded for the underlying cause of death according to the International Classification of Diseases, 9th Revision. Because the Social Security Adminstration master death file was not completely accurate, the National Death Index was also used. Studies were conducted on the relationships of isolated systolic hypertension to stroke and coronary heart disease mortality, and on seasonal and regional variations in cardiovascular mortality. Using data from the Census Bureau (education and income levels by zip code), the socio-economic status of participants was indirectly estimated and the coronary heart disease and cancer death rate differences between white and Black men were evaluated by social class. Studies were also conducted on the associations of cause- specific cancer mortality and serum cholesterol concentration, and on the association of serum cholesterol, diastolic blood pressure, and cigarettes smoked per day with mortality from coronary heart disease and cerebrovascular disease for Black and white men.