Cigarette smoking and age at natural menopause.

In a cohort of 656 naturally postmenopausal women who were interviewed at age 60 to 69 years, and was had reached their menopause between the ages of 35 and 59 years, the mean age at menopause declined with increasing number of cigarettes smoked, from 49.4 years of age among women who had never smoked to 47.6 years of age among women who smoked at least 15 cigarettes per day (p less than 0.02). The relationship was not attributable to the onset of menopause inducing women to take up smoking.