Association of diet with the onset of menopause in Japanese women

A prospective study was conducted in Takayama, Gifu, Japan, to evaluate the association between diet and the onset of menopause. A total of 1,130 fema le residents aged 35-54 years who were premenopausal and completed a valida ted semiquantitative food frequency questionnaire in 1992 were contacted by mail with a follow-up questionnaire in 1998 to update information on menop ause. Onset of menopause was defined as a woman's age at the last menstrual period prior to stopping menstruation for 12 months. During the 6-year stu dy period, 296 women experienced natural menopause. The Cox proportional ha zards model was used to estimate hazard ratios of the onset of menopause af ter controlling for age, total energy, body mass index, years of smoking, a nd age at which regular menstrual cycle began. The authors found that green and yellow vegetable intake was significantly inversely associated with th e 6-year incidence of menopause (hazard ratio = 0.71, 95% confidence interv al: 0.54, 0.95 for the highest vs. lowest tertile of intake, p for trend = 0.02). Association of carotene intake with the incidence of menopause was o f borderline significance (hazard ratio = 0.78, 95% confidence interval: 0. 59, 1.04, p for trend = 0.07).