Many women take supplemental estrogens after menopause, a practice called hormone replacement therapy (HRT). Moderate alcohol consumption may increase estrogen levels in women receiving HRT, potentially affecting their risk for various adverse health effects. Two recent studies, however, provide no strong evidence for an effect of alcohol on hormones in postmenopausal women. The possible association between alcohol consumption and risk of cancer of the breast does not appear to be mediated by estrogens. Both estrogens and moderate alcohol consumption have been associated with a decreased risk for cardiovascular disease; however, alcohol's beneficial effect on heart disease does not appear to involve hormonal mechanisms. Additional research is needed to define the consequences of moderate drinking on hormone levels after menopause. KEY WORDS: AODE (alcohol and other drug effects); menopause; female; sex hormones; estrogens; mammary gland; neoplastic disease; cardiovascular disorder; moderate AOD use; drug therapy; literature review
Approximately 30 percent of American women are older than age 50, the average age of menopause (Cramer and Xu 1996).1 Epidemiological studies suggest that approximately 50 percent of women in this age group consume at least moderate quantities of alcohol (National Institute on Alcohol Abuse and Alcoholism [NIAAA] 1997).2 Therefore, any adverse effects of alcohol among this population could have a significant effect on public health.
Menopause is characterized by greatly diminished levels3 of a group of steroid reproductive hormones called estrogens. Estrogens (e.g., estrone and estradiol) travel through the bloodstream and exert widespread physiological effects on organ growth and development. Approximately 25 percent of postmenopausal women take supplemental estrogens to alleviate unpleasant symptoms of menopause, a practice called hormone replacement therapy (HRT) (Ginsburg et al. 1996). Estrogens have various effects on the health of postmenopausal women (Rich-Edwards and Hennekens 1996). For example, HRT decreases the risk of cardiovascular disease and osteoporosis4 but may increase the risk of breast cancer (Ginsburg et al. 1996). Recent experimental studies show that moderate alcohol consumption may increase estrogen levels in postmenopausal women receiving HRT (Ginsburg et al. 1996).
This article reviews some of the basic hormonal changes associated with menopause, examines the effects of alcohol consumption on estrogen levels after menopause, and discusses the relationship of postmenopausal alcohol use to the risks of cardiovascular disease and cancer. Although several reproductive hormones may play important roles in the menopausal transition, this article focuses on estrogens, in part because the health effects of altered estrogen levels are relatively well understood. For a discussion of alcohol's effects on postmenopausal women with alcoholic cirrhosis, see Gavaler (1995)
HORMONAL FUNCTION BEFORE MENOPAUSE
The female reproductive cycle is governed primarily by two groups of hormones: the gonadotropins and the steroid reproductive hormones. The gonadotropins include folliclestimulating hormone (FSH) and luteinizing hormone (LH), which are produced by the pituitary gland and released into the bloodstream. The steroid reproductive hormones are produced largely in the ovaries. Approximately every 28 days, levels of FSH and LH in the blood begin to increase, stimulating the growth and development of specialized cell clusters (i.e., follicles) within the ovaries. Each follicle nurtures a developing egg cell (i.e., ovum) and secretes estrogens. Within the ovaries, estrogens help promote follicular development. A midcycle surge of LH secretion from the pituitary gland causes the release of a mature ovum, which then migrates away from the ovaries. Under the influence of LH, the ovary continues to secrete estrogens and other steroid hormones to prepare the body for pregnancy and lactation. …