title: Coffee consumption and risk of breast cancer: an up-to-date meta-analysis.
abstract: OBJECTIVE
  This updated meta-analysis was conducted to assess the association between coffee consumption and breast cancer risk.
  
  
  METHODS
  We conducted a systematic search updated July 2012 to identify observational studies providing quantitative estimates for breast cancer risk in relation to coffee consumption. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and generalized least square trend estimation was used to assess dose-response relationships.
  
  
  RESULTS
  A total of 26 studies (16 cohort and 10 case-control studies) on coffee intake with 49497 breast cancer cases were included in the meta-analysis. The pooled RR showed a borderline significant influence of highest coffee consumption (RR = 0.96; 95% CI 0.93-1.00), low-to moderate coffee consumption (RR = 0.99; 95% CI 0.95-1.04), or an increment of 2 cups/day of coffee consumption (RR = 0.98; 95% CI 0.97-1.00) on the risk of breast cancer. In stratified analysis, a significant inverse association was observed in ER-negative subgroup. However, no significant association was noted in the others.
  
  
  CONCLUSIONS
  Our findings suggest that increased coffee intake is not associated with a significantly reduced risk of breast cancer, but we observe an inverse association in ER-negative subgroup analysis. More large studies are needed to determine subgroups to obtain more valuable data on coffee drinking and breast cancer risk.
authors: Department of Oncology, Xuzhou Medical College, Xuzhou, People's Republic of China.
authors: Xiu Juan
authors: XJ
authors: Li
authors: Zhao Jun
authors: ZJ
authors: Ren
authors: Jian Wei
authors: JW
authors: Qin
authors: Jian Hua
authors: JH
authors: Zhao
authors: Jin Hai
authors: JH
authors: Tang
authors: Ming Hua
authors: MH
authors: Ji
authors: Jian Zhong
authors: JZ
authors: Wu
mesh_terms: D001943:Breast Neoplasms / Q000209:etiology*; D016022:Case-Control Studies; D003069:Coffee; D015331:Cohort Studies; D005260:Female; D006801:Humans; D011960:Receptors, Estrogen / Q000032:analysis; D012307:Risk Factors
chemical_list: D003069:Coffee; D011960:Receptors, Estrogen