Secular blood pressure trends in normotensive persons: the Framingham Study

Trends in hypertension prevalence are difficult to assess because of a massive increase in the prevalence of antihypertensive treatment. Over the past three decades mean blood pressure levels among the 5209 members of the Framingham Study cohort have declined, and elevated blood pressure is only one third as prevalent. However, if those receiving treatment who have normalized blood pressures are defined as hypertensive, in addition to those with elevated blood pressure, the prevalence of hypertension has increased. No consistent secular trend in the incidence of hypertension was noted over three decades, but high blood pressure eventually developed in two thirds of the study cohort. To determine whether untreated blood pressure levels are changing over time, trends in mean blood pressure were examined in normotensive subjects over three decades. Only a 1 mm Hg decline in mean systolic and diastolic pressure over each 10-year interval was noted (p < 0.001). Thus blood pressure in the normotensive segment of the population has been quite stable. Because the incidence of hypertension is very high and future hypertension arises from the upper end of the normal blood pressure distribution, there is an urgent need for primary prevention. Preventive measures such as exercise, avoidance of salt and alcohol, and especially weight control deserve a high priority.