This prospective study re-examined the 5,500 residents of Gubbio who took part in the Gubbio Population Study in 1983-1985. The data collected on follow-up focused mainly on factors related to change in blood pressure and development of hypertension and included standard physical examination, height, weight, girth, blood pressure, medical history and family medical history, urine collection for study of electrolyte excretion, venipuncture, 12-lead electrocardiogram, m-mode echocardiogram, pulse, skinfold measurement, carbon monoxide content of exhaled breath, sociodemographic data on age, marital status, education, and employment, and life style data on diet, alcohol intake, smoking, and physical activity.