Normotensive middle-aged men after 5-10 years: normal blood pressure or hypertension?

We evaluated the incidence of hypertension over 5-10 years of follow-up in middle-aged men, 40-59 years at entry, selected from the Italian section of the Seven Countries Study. Out of the 2480 subjects, 852 were normotensive at entry [systolic blood pressure (SBP) less than 140 mmHg and diastolic blood pressure (DBP) less than 90 mmHg)], alive after 10 years and had been evaluated repeatedly after 5 and 10 years. After 5 years, 31.3\% had developed borderline hypertension (140 less than or equal to SBP less than 160 and 90 less than or equal to DBP less than or equal to 95 mmHg) and 14.6\% had developed definite hypertension (SBP greater than or equal to 160 mmHg or DBP greater than or equal to 95 mmHg). During the next 5 years, out of the 267 borderline hypertensives, 28.5\% became definite hypertensives, while 29.6\% reverted to normal blood pressure. Out of the 124 definite hypertensives, 46\% remained in this category, while 34.7\% became borderline hypertensives and 19.4\% became normotensive. In men aged 60-69 years, less than 2\% of hypertensives were being effectively treated and changes in body weight were closely related to blood pressure. In addition, out of 461 normotensive subjects who remained normotensive at the 5-year examination, 63.6\% remained normotensive in the next 5 years also, while 28\% developed borderline hypertension and only 8.4\% moved into the definite hypertensive class. These data suggest that a normotensive subject aged 40-59 years has a 34.4\% probability of remaining normotensive in the next 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)