title: Alcohol, caffeine and smoking in relation to age at menopause.
abstract: OBJECTIVE
  Exposures which might influence age at natural menopause have been extensively studied but, with the exception of cigarette smoking, results have been inconsistent. We sought to determine: (i) whether alcohol and caffeine intake are associated with age at menopause; (ii) whether the association of cigarette smoking with age at menopause is confined to current smokers.
  
  
  METHODS
  Analyses drew on longitudinal data from 494 women, aged 44-60 in 1993, of whom 159 experienced menopause before intake or during follow-up. We used parametric logistic survival analysis to estimate shifts in median age at menopause for women who drink alcohol or caffeine or who smoke cigarettes.
  
  
  RESULTS
  The estimated median age at menopause was 2.2 (95% confidence interval (CI) 0.5, 3.9) years later for women who drank alcohol 5-7 days/week (13% of the sample) than for women who did not drink alcohol (54%). For women who drank at least 1 day/week, the estimated shift was 1.3 (95% CI 0.2, 2.3) years. Caffeine intake in approximate quartiles of mg/day-0-100, >100-200, >200-400, 400+-was not related to age at menopause. Current smokers of 14+cigarettes/day (6%) experienced menopause 2.8 (95% CI -4.8, -0.8) years earlier than women who never smoked (51%). Current smokers of 1-13 cigarettes/day (5%) and former smokers (38%) experienced menopause at about the same age as women who never smoked.
  
  
  CONCLUSIONS
  The results are compatible with a pro-estrogenic effect of moderate alcohol intake and an anti-estrogenic effect of current cigarette smoking of 14+cigarettes/day.
authors.affiliation: Department of Epidemiology, Graduate School of Arts and Sciences, Columbia University, New York, NY 10032, USA. amk13@columbia.edu
authors.forename: Ann
authors.initials: A
authors.lastname: Kinney
authors.forename: Jennie
authors.initials: J
authors.lastname: Kline
authors.forename: Bruce
authors.initials: B
authors.lastname: Levin
mesh_terms: D000328:Adult; D017668:Age of Onset; D000428:Alcohol Drinking / Q000453:epidemiology*; D002110:Caffeine / Q000008:administration & dosage*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008593:Menopause; D008875:Middle Aged; D009519:New York City / Q000453:epidemiology; D012907:Smoking / Q000453:epidemiology*
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine