High density lipoprotein cholesterol, total cholesterol screening, and myocardial infarction. The Framingham Study

Abstract

The relation between high density lipoprotein cholesterol (HDL-C) and the development of myocardial infarction was examined in 2425 subjects, aged 50 to 79 years, who were enrolled in the Framingham Study from 1969 to 1971. After twelve years of follow-up, men in the bottom three quartiles of HDL-C (≤ 52 mg/dl) experienced a 60% to 70% excess of myocardial infarction as compared to men whose HDL-C levels were higher (p < 0.05). The effect of HDL-C was especially strong in women. In separate comparisons to the 4th quartile of HDL-C (≥ 67 mg/dl), the risk of myocardial infarction increased from a fourfold excess in the adjacent 3rd quartile (56 to 66 mg/dl, p < 0.01) to a nearly sixfold excess in the 1st quartile (≤ 46 mg/dl, p < 0.001). These results persisted after adjusting for age and other risk factors. In addition, a significant effect of HDL-C remained in subjects who had the lowest concentrations of total cholesterol (≤ 192 mg/dl in men and 211 mg/dl in women) in which 29% had levels of HDL-C (≤ 36 mg/dl in men and 46 mg/dl in women) that were associated with a marked elevation in the incidence of myocardial infarction. We conclude that screening for total cholesterol alone in men and women aged 50 and older may not adequately identify the coronary candidate. In addition, selective screening of HDL-C only for individuals with high concentrations of total cholesterol can leave the false impression that low total cholesterol is uniformly associated with a healthy risk profile.