BACKGROUND:

The field work of the baseline or prevalence phase of the Gubbio Study on the Epidemiology of Hypertension was conducted between March 1983 and December 1985. The population sample included all individuals age 5 and over residing in the town of Gubbio. The survey involved a standardized comprehensive examination focussed on traits previously shown to be related to hypertensive and/or other adult cardiovascular diseases, and on other traits of current concern as possible risk factors. This latter category included measurement of red blood cell electrolyte concentrations and fluxes, particularly sodium-stimulated lithium countertransport. The study was planned, organized, and conducted by the Merck, Sharp and Dohme Center for Epidemiologic Research in cooperation with Gubbio civic and medical leaders, and with laboratory facilities in Gubbio, Naples, and Rome.

Follow-up examinations were conducted in the Centro di Medicina Preventiva in Gubbio which was furnished and equipped by Merck, Sharp and Dohme of Rome, Italy. Additional work was conducted at the Center for Epidemiologic Research of Merck, Sharp and Dohme in Rome, at the University of Naples, and at Northwestern University in Chicago.

DESIGN NARRATIVE:

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.

Measurements made at baseline permitted assessment of whether the hypothesized positive relation of lithium countertransport to blood pressure was independent of such factors as age, sex, body mass index, alcohol intake, plasma uric acid, glucose, family history, and other variables generally associated with blood pressure. The relationship between 5-year changes in these factors, change in lithium countertransport, and in blood pressure were also examined. Several additional important unresolved questions on the epidemiology of blood pressure and hypertension were explored: the role of macronutrients and micronutrients in lithium countertransport and its change; red blood cell sodium and potassium concentrations and their relation to blood pressure; possible differences in calcium metabolism between hypertensives and normotensives; genetic polymorphisms related to lipid-lipoprotein metabolism and possible influence on blood pressure; patterns of blood pressure change in the elderly, the 639 and 341 persons age 65-74 and over 75, respectively, at baseline. Coronary heart disease incidence was also studied.