Relation of Low Body Mass to Death and Stroke in the Systolic Hypertension in the Elderly Program

Abstract

THERE HAS been much emphasis on obesity as a risk factor for cardiovascular disease and mortality,^1-4 but there has been no comparable focus on possible risks associated with leanness. Many studies^5-8 have found a U- or J-shaped relation between body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) and mortality. Others,^2,9,10 however, have found a strong and direct relation between BMI and cardiovascular disease and mortality. These studies have helped to disseminate the widespread belief that losing weight is universally desirable. The association between low levels of BMI and mortality has often been explained as being due to confounding, by smoking, for example,⁸ or to preexisting illness. However, studies^2,3 that control for confounders and that exclude events occurring during the first period of follow-up still find a residual J- or U-shaped relation. Whether early or chronic obesity confers the excess risk observed at high levels of BMI and whether weight loss or a low BMI per se confers the excess risk at low levels of BMI are not established. Little attention has been devoted to BMI and risk in older persons or in those with an existing recognized comorbid condition. This article presents data on the relation of BMI with death and stroke in a cohort of older persons enrolled in the Systolic Hypertension in the Elderly Program (SHEP), a placebo-controlled, randomized, clinical trial of antihypertensive therapy for isolated systolic hypertension.