High density lipoprotein as a protective factor against coronary heart disease. The Framingham Study

Lipid and lipoprotein values, including fasting triglycerides and high density lipoproteins (HDL), low density lipoproteins (LDL) and total cholesterol levels, were obtained on 2,815 men and women aged 49 to 82 years chiefly between 1969 and 1971 at Framingham. In the approximately four years following the characterization of lipids, coronary heart disease developed in 79 of the 1,025 men and 63 of the 1,445 women free of coronary heart diseases. At these older ages the major potent lipid risk factor was HDL cholesterol, which had an inverse association with the incidence of coronary heart disease (p less than 0.001) in either men or women. This lipid was associated with each major manifestation of coronary heart disease. These associations were equally significant even when other lipids and other standard risk factors for coronary heart disease were taken into consideration. A weaker association with the incidence of coronary heart disease (p less than 0.05) was observed for LDL cholesterol. Triglycerides were associated with the incidence of coronary heart disease only in women and then only when the level of other lipids was not taken into account. At these ages total cholesterol was not associated with the risk of coronary heart disease.