Background: Cardiovascular disease is the leading cause of death in women, with most deaths occurring after menopause. It had been assumed that lack of estrogen is a leading contributing factor to cardiovascular disease in women. Recent trials, however, using hormone replacement therapy to treat cardiovascular disease in women have not affirmed the cardiovascular benefits ascribed to this regimen. Ovarian function declines slowly over the decades approaching the menopause as evidenced by declining fertility, rising serum FSH, falling inhibin, yet normal estradiol levels. We investigated the relationship between basal FSH and an established major risk factor for cardiovascular disease.
Methods and results: We obtained cycle day 3 serum FSH levels and fasting lipoprotein profiles on 40 women between the ages of 29 and 49 years, with normal menstrual cycles and who were not using hormonal medications or statins. Premenopausal women with an FSH level > or =7 IU/l had significantly elevated total cholesterol (P=0.009) and LDL (P=0.019) compared with those with FSH <7 IU/l. This difference was independent of age. Neither HDL nor triglyceride levels differed between the two groups.
Conclusions: Decreased functional ovarian reserve, as approximated by serum day 3 FSH levels, correlates with known cardiovascular risk factors. Declining ovarian function prior to estrogen deficiency may be a cardiac risk factor. The premenopausal ovary may be a source of cardioprotective substance other than estradiol. We hypothesize that factors other than 17beta-estradiol, but related to ovarian function, might contribute to cardiovascular risk.