title: Coffee consumption and risk of breast cancer: a metaanalysis.
abstract: OBJECTIVE
  This metaanalysis was conducted to assess the association between coffee consumption and breast cancer risk.
  
  
  METHODS
  Relevant studies were identified by searching Medline (1966-May 2008) and the reference lists of retrieved articles. The summary relative risk (RR) with 95% confidence interval (CI) was calculated using a random-effects model.
  
  
  RESULTS
  Nine cohort and 9 case-control studies met the inclusion criteria. The combined RR showed a borderline significant influence of highest coffee consumption (RR, 0.95; 95% CI, 0.90-1.00) or an increment of 2 cups/day of coffee consumption (RR, 0.98; 95% CI, 0.96-1.00) on the risk of breast cancer. In stratified analysis, borderline significant associations were observed among cohort and case-control studies and studies conducted in Europe and the United States. However, no significant association was noted among studies conducted in Asia.
  
  
  CONCLUSIONS
  Our findings suggest a possible influence of high coffee consumption or an increased coffee consumption on the risk of breast cancer.
authors.affiliation: National Shanghai Center for New Drug Safety Evaluation and Research, Shanghai Institute of Pharmaceutical Industry, Shanghai, China. naping.tang@gmail.com
authors.forename: Naping
authors.initials: N
authors.lastname: Tang
authors.forename: Bo
authors.initials: B
authors.lastname: Zhou
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Rongbin
authors.initials: R
authors.lastname: Yu
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology*; D002110:Caffeine / Q000009:adverse effects*; D016022:Case-Control Studies; D000697:Central Nervous System Stimulants / Q000009:adverse effects*; D003069:Coffee / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D012307:Risk Factors
chemical_list: D000697:Central Nervous System Stimulants; D003069:Coffee; D002110:Caffeine