Background: Previous estimates of the population-wide impact of nonpharmacologic interventions that lower blood pressure (BP) have typically assumed a uniform response to the intervention. However, several nonpharmacologic interventions reduce BP to a greater degree in hypertensives and African-Americans.
Methods: We used the Framingham risk equation and data from the Third National Health and Nutrition Examination Survey (NHANES III) to estimate the number of coronary heart disease (CHD) events that would be prevented in the United States assuming a population-wide adoption of the DASH (Dietary Approaches to Stop Hypertension) diet under three scenarios: (1) an overall uniform systolic blood pressure (SBP) shift, (2) race-specific uniform SBP shifts, and (3) race-specific progressive SBP shifts. The uniform shifts were the mean SBP reductions from the DASH trial. The progressive shifts were derived by modeling the change in SBP as a function of baseline SBP in DASH.
Results: Applying an overall uniform SBP reduction of 5.5 mm Hg (the mean reduction in DASH), we predicted a reduction of 668,426 CHD events over 10 years (60,230 in African-Americans and 608,196 in whites). Applying race-specific uniform SBP reductions (6.8 mm Hg for African-Americans and 3.0 mm Hg for whites), we predicted a reduction of 406,432 CHD events (74,401 in African-Americans and 332,031 in whites). After accounting for race and baseline SBP, we predicted a reduction of 416,514 CHD events (94,828 in African-Americans and 321,080 in whites). While whites would be expected to have a greater absolute reduction in CHD events, African-Americans would be expected to experience a greater relative reduction in CHD events.
Conclusion: Models that estimate the population-wide impact of BP reduction strategies should take into account the baseline distribution of BP and differential effects in subgroups. Population-wide adoption of a healthy dietary pattern should have a substantial impact on the incidence of CHD in the United States, especially among African-Americans. Additional studies are needed to assess the impact of the DASH diet on CHD risk in free-living subjects.