title: Coffee consumption and risk of prostate cancer: an up-to-date meta-analysis.
abstract: OBJECTIVE
  Epidemiologic findings concerning the association between coffee consumption and prostate cancer risk yielded mixed results. We aimed to investigate the association by performing a meta-analysis of all available studies.
  
  
  METHODS
  We searched PubMed, Web of Science and EMBASE for studies published up to July 2013. We calculated the summary relative risk (RR) and 95% confidence intervals (CIs) for ever, moderate and highest consumption of coffee vs non/lowest consumption. The dose-response relationship was assessed by restricted cubic spline model and multivariate random-effect meta-regression.
  
  
  RESULTS
  A total of 12 case-control studies and 12 cohort studies with 42,179 cases were selected for final meta-analysis. No significant associations were found among overall analysis. A borderline positive association was found for highest drinkers in five small hospital-based case-control (HCC) studies involving 2278 cases. However, compared with non/lowest drinkers, the summary RRs were 0.92 (95% CI=0.85-0.99) for ever drinkers, 0.92 (95% CI=0.85-1.00) for moderate drinkers and 0.83 (95% CI=0.72-0.96) for highest drinkers from 12 cohort studies, comprising a total of 34,424 cases. An increase in coffee intake of two cups/day was associated with a 7% decreased risk of prostate cancer according to cohort studies. A significant inverse relationship was also found for fatal prostate cancers and high-grade prostate cancers.
  
  
  CONCLUSIONS
  Case-control studies especially HCC ones might be prone to selection bias and recall bias that might have contributed to the conflicting results. Therefore, the present meta-analysis suggests a borderline significant inverse association between coffee consumption and prostate cancer risk based on cohort studies.
authors.affiliation: Center of Clinical Laboratory Science, Jiangsu Cancer Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors.forename: S
authors.initials: S
authors.lastname: Zhong
authors.affiliation: The Fourth Clinical College of Nanjing Medical University, Nanjing, China.
authors.forename: W
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Hematology (Key Department of Jiangsu Medicine), Zhongda Hospital, Medical School, Southeast University, Nanjing, China.
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of General Surgery, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Teaching and Research Office of General Surgery, Xuzhou Medical College, Xuzhou, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Center of Clinical Laboratory Science, Jiangsu Cancer Hospital Affiliated to Nanjing Medical University, Nanjing, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhao
mesh_terms: D003069:Coffee / Q000009:adverse effects; D016001:Confidence Intervals; D016208:Databases, Factual; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000209:etiology / Q000517:prevention & control*; D012307:Risk Factors
chemical_list: D003069:Coffee