IMPLICATIONS OF SMALL REDUCTIONS IN DIASTOLIC BLOOD-PRESSURE FOR PRIMARY PREVENTION

Objectives: To estimate the impact of small reductions in the populati on distribution of diastolic blood pressure (DBP), such as those poten tially achievable by population-wide lifestyle modification, on incide nce of coronary heart disease (CHD) and stroke. Design: Published data from the Framingham Heart Study, a longitudinal cohort study, and fro m the National Health and Nutrition Examination Survey II, a national population survey, were used to examine the impact of a population-wid e strategy aimed at reducing DBP by an average of 2 mm Hg in a populat ion including normotensive subjects. Setting/Participants: White men a nd women aged 35 to 64 years in the United States. Main Outcome Measur es: Incidence of CHD and stroke, including transient ischemic attacks (TIAs). Results: Data from overviews of observational studies and rand omized trials suggest that a 2-mm Hg reduction in DBP would result in a 17% decrease in the prevalence of hypertension as well as a 6% reduc tion in the risk of CHD and a 15% reduction in risk of stroke and TIAs . From an application of these results to US white men and women aged 35 to 64 years, it is estimated that a successful population intervent ion alone could reduce CHD incidence more than could medical treatment for all those with a DBP of 95 mm Hg or higher. It could prevent 84% of the number prevented by medical treatment for all those with a DBP of 90 mm Hg or higher. For stroke (including TIAs), a population-wide 2-mm Hg reduction could prevent 93% of events prevented by medical tre atment for those with a DBP of 95 mm Hg or higher and 69% of events fo r treatment for those with a DBP of 90 mm Hg or higher. A combination strategy of both a population reduction in DBP and targeted medical in tervention is most effective and could double or triple the impact of medical treatment alone. Adding a population-based intervention to exi sting levels of hypertension treatment could prevent an estimated addi tional 67 000 CHD events (6%) and 34 000 stroke and TIA events (13%) a nnually among all those aged 35 to 64 years in the United States. Conc lusions: A small reduction of 2 mm Hg in DBP in the mean of the popula tion distribution, in addition to medical treatment, could have a grea t public health impact on the number of CHD and stroke events prevente d. Whether such DBP reductions can be achieved in the population throu gh lifestyle interventions, in particular through sodium reduction, de pends on the results of ongoing primary prevention trials as well as t he cooperation of the food industry, government agencies, and health e ducation professionals.