Atherogenesis: why women live longer than men

Abstract

The total LDL:HDL cholesterol ratio, at higher levels, appears sufficient to account for the risk of clinical atherosclerosis in both sexes. At lower levels, however, women continue to enjoy less risk of atherosclerosis even at LDL:HDL cholesterol ratios equivalent to those in men. Median LDL levels are higher in men than in women until the menopause, beyond which a crossover occurs, and median levels become higher in women. However, though the difference narrows in the post-menopausal years, the LDL:HDL ratio is never higher in women than in men.

PIP: This article addresses the question of why women seem to be more protected than men from the consequences of premature atherosclerosis. At higher levels, the total low density lipoprotein (LDL): high density lipoprotein (HDL) cholesterol ratio seems to account for the risk of atherosclerosis in both sexes. However, at lower levels, women appear to be at less risk of atherosclerosis than men even when LDL: HDL cholesterol ratios are equivalent. The median LDL level is greater in males from puberty until menopause, and greater in females after menopause. Although gender differences narrow in the postmenopausal period, the LDL: HDL ratio is always higher in men. Thus, it is hypothesized that the sex differential in the secretion of sex hormones accounts for the sex differential in lipoproteins, which in turn explains the sex differential in atherogenic risk and produces sex differences in relative longevity. Consistently lower levels of LDL and higher levels of HDL cholesterol have been noted among women taking exogenous estrogens for postmenopausal replacement compared with women not taking hormones. Studies of various combinations of oral contraceptives have indicated that the strength of the progestin component compared to that of estrogen determines whether HDL levels are higher, the same, or lower than in women not taking these preparations. In contrast, the administration of androgenic substances to postmenopausal women is associated with increases in LDL cholesterol and decreases in HDL cholesterol.