title: Coffee consumption and prostate cancer risk: an updated meta-analysis.
abstract: OBJECTIVE
  Many epidemiological studies have been conducted to explore the association between coffee consumption and prostate cancer. However, the results remain inconsistent. We performed a large meta-analysis of relevant studies to derive a more precise estimation of this relationship.
  
  
  METHODS
  Systematic searches of PubMed and several other databases up to June 2013 were retrieved. All epidemiologic studies regarding coffee consumption and prostate cancer risk were included, and odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated to estimate the strength of the association.
  
  
  RESULTS
  Twelve case-control studies involving 7,909 prostate cancer cases and 9,461 controls and nine cohort studies involving 455,123 subjects were included in our analysis. Compared with the lowest category, the unstratified highest category of coffee consumption showed a significance reduction in prostate cancer risk of a fixed-effects model (OR 0.91, CI 0.86-0.97). A borderline significant influence was also found when the stratified highest category (US ≥ 4, Europe ≥ 5) of coffee consumption was compared with the reference category (OR 0.96, CI 0.92-1.00), but no relationships were observed for the other two categories. In another analysis conducted by coffee consumption and prostate cancer stage and Gleason grade, our results showed a significant inverse association in all categories of prostate cancer except Gleason <7 grade in a fixed-effects model; the results remained the same, except for advanced prostate cancer, in a random-effects model.
  
  
  CONCLUSIONS
  Our meta-analysis suggests that high (e.g., highest ≥ 4 or 5 cups/day) coffee consumption may not only be associated with a reduced risk of overall prostate cancer, but also inversely associated with fatal and high-grade prostate cancer.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lu
authors.forename: Limin
authors.initials: L
authors.lastname: Zhai
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng
authors.forename: Qiliu
authors.initials: Q
authors.lastname: Peng
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.forename: Cuiju
authors.initials: C
authors.lastname: Mo
authors.forename: Shi
authors.initials: S
authors.lastname: Yang
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
mesh_terms: D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003069:Coffee; D015331:Cohort Studies; D004327:Drinking Behavior; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000453:epidemiology*; D012307:Risk Factors
chemical_list: D003069:Coffee