The relationship between body mass index and pulse pressure in older adults with isolated systolic hypertension

Background: Many longitudinal studies have reported excess cardiovascular mortality among lean hypertensive subjects, suggesting that obesity may mitigate the cardiovascular risk of hypertension. Available evidence also suggests that in middle-aged and older hypertensive subjects, pulse pressure may be a better predictor of cardiovascular complications. However, there are limited data on the relationship between body mass index (BMI) and pulse pressure. Methods: Using data from the Third National Health and Nutrition Examination Survey we assessed the convergence validity of pulse pressure as a predictor of cardiovascular complications and examined the relationship between BMI and pulse pressure in 1192 older adults with isolated systolic hypertension who were not receiving blood pressure medicine. Results: There was a good concordance between high pulse pressure and most of the selected cardiovascular risk factors examined in this study. Pulse pressure is higher in the lean (BMI <25) than in the overweight (BMI 25; 79 rum Hg vs 74 rum Hg, P <.001) and decreases significantly from 82 mm Hg in the first BMI quintile to 76 mm Hg in the fifth BMI quintile. Pulse pressure continues to decrease with increasing BMI until the index exceeds 30.1. This negative correlation persists in a multivariate model with statistical adjustment for age, sex, diabetes mellitus, and hypercholesterolemia. Conclusion: The inverse relation between BMI and pulse pressure observed here may help to explain previous reports of increased cardiovascular risk among lean versus obese subjects with isolated systolic hypertension.