title: Caffeine, alcohol, smoking, and the risk of incident epithelial ovarian cancer.
abstract: BACKGROUND
  Smoking, caffeine, and alcohol intake are all potentially modifiable factors that have an unclear association with ovarian cancer risk. Therefore, the associations between these exposures and ovarian cancer risk were prospectively examined among 110,454 women in the Nurses' Health Study (NHS) for the smoking analyses and 80,253 women for the dietary analyses.
  
  
  METHODS
  Women completed biennial questionnaires assessing ovarian cancer risk factors beginning in 1976, with food frequency questionnaires administered every 2 to 4 years starting in 1980. For the smoking analyses, 737 confirmed cases of epithelial ovarian cancer were identified and for the dietary aims, 507 cases were identified through June 1, 2004.
  
  
  RESULTS
  Compared with never-smokers, neither current nor past smoking was associated with ovarian cancer risk overall; however, both were associated with mucinous tumors (n = 69; rate ratio [RR], past = 2.02 [95% confidence interval (CI), 1.15-3.55]; RR, current = 2.22 [95% CI, 1.16-4.24]). A modest inverse association between caffeine intake and ovarian cancer risk was observed (RR, top vs bottom quintile = 0.80; 95% CI, 0.60-1.07 [P = .03]), which was strongest for women who had never used either oral contraceptives (RR = 0.65; 95% CI, 0.46-0.92 [P for heterogeneity = .02]) or postmenopausal hormones (RR = 0.57; 95% CI, 0.36-0.91 [P for heterogeneity = .13]). Alcohol was not associated with ovarian cancer risk.
  
  
  CONCLUSIONS
  The results of the current study suggest that cigarette smoking may only increase the risk for mucinous ovarian tumors, and alcohol intake was not associated with risk. However, an inverse association was observed between caffeine intake and ovarian cancer risk, particularly in women not using hormones; this finding merits further study.
authors.affiliation: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. nhsst@channing.harvard.edu
authors.forename: Shelley S
authors.initials: SS
authors.lastname: Tworoger
authors.forename: Dorota M
authors.initials: DM
authors.lastname: Gertig
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Gates
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Hecht
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hankinson
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D002110:Caffeine / Q000009:adverse effects*; D003069:Coffee / Q000009:adverse effects; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000139:chemically induced / Q000453:epidemiology*; D010051:Ovarian Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
chemical_list: D003069:Coffee; D002110:Caffeine