Active and passive smoking and the occurrence of natural menopause

We examined smoking in relation to natural menopause in 543 women who prosp ectively recorded menstrual data from their 20s. Mean age at natural menopa use was 0.8 years younger (95% CL = -1.5, -0.0) in 98 women who smoked at m enopause compared with 362 never-smokers (RR 1.3, 95% CI = 1.0-1.7). We did not observe a decrease in age at natural menopause in former smokers, a do se-response among current smokers, or a lower age at menopause with passive smoke exposure at home. These results suggest that the effect of smoking o n ovarian senescence is limited to active smoking during the menopausal tra nsition.