Health policy on blood cholesterol. Time to change directions.

U-shaped association between the level of blood A cholesterol and subsequent mortality has been reported in many studies over the past two decades.1-3 The right-hand limb of the U is the well known higher risk of death from coronary heart disease (CHD) at higher levels of blood cholesterol; this positive association, shown in clinical trials to be causal and reversible, is the cornerstone of U.S. policies directed at lowering high blood cholesterol.4 The left-hand limb of the U is the higher risk of deaths from non-CHD causes at lower levels of blood cholesterol; the basis for this negative association remains poorly understood, and its implications for health policy have received inadequate attention.5,6 This issue of Circulation contains a report on the 1990 National Heart, Lung, and Blood Institute Conference on Low Blood Cholesterol: Mortality Associations that presents a statistical overview of available cohort studies. The unprecedented size of the study (68,406 deaths)