Factors associated with early menopause.

An understanding of why certain factors contribute to a more rapid decline in ovarian function may, for some women, help prevent premature loss of fecundity and the subsequent impact of health problems secondary to long-term estrogen deficiency such as osteoporosis, cardiovascular disease, and possibly Alzheimer's disease. A summary of the evidence regarding factors that have been proposed to contribute to an early onset of natural menopause is presented. These factors include cigarette smoking, race, education, parity, menstrual cycle length, the use of oral contraceptives, age at menarche, major depression, anthropometry, and handedness. Cigarette smoking has been found to hasten the onset of menopause by as much as one year. Lifetime number of ovulatory cycles (indicative of oocyte depletion) is also predictive of the age at natural menopause (ANP). This is consistent with the many studies that have reported early ANP among women with shorter menstrual cycles, and a later ANP among multigravid women or those who used oral contraceptives. The relationship between depressive disorder and ovarian failure is complex, involving consideration of the pharmacological effects of treatment, and is currently unclear. The findings regarding an effect of body mass index on ANP are also mixed. At this time, there is little persuasive evidence that handedness or demographic characteristics (independent of their relationship with behavioral factors like smoking) influence the ANP to any substantial degree. Some factors that could potentially influence ANP have been identified, but these and other avenues of investigation warrant further study.