title: Fish consumption and colorectal cancer risk in humans: a systematic review and meta-analysis.
abstract: BACKGROUND
  Fish consumption may protect against colorectal cancer, but results from observational studies are inconsistent; therefore, a systematic review with a meta-analysis was conducted.
  
  
  METHODS
  Relevant studies were identified by a search of MEDLINE and EMBASE databases to May 2011, with no restrictions. Reference lists from retrieved articles also were reviewed. Studies that reported odds ratio (OR) or relative risk estimates with 95% confidence intervals (CIs) for the association between the consumption of fish and the risk of colorectal, colon, or rectal cancer were included. Two authors independently extracted data and assessed study quality. The risk estimate (hazard ratio, relative risk, or OR) of the highest and lowest reported categories of fish intake were extracted from each study and analyzed using a random-effects model.
  
  
  RESULTS
  Twenty-two prospective cohort and 19 case-control studies on fish consumption and colorectal cancer risk met the inclusion criteria and were included in the meta-analysis. Our analysis found that fish consumption decreased the risk of colorectal cancer by 12% (summary OR, 0.88; 95% CI, 0.80-0.95). The pooled ORs of colorectal cancer for the highest versus lowest fish consumption in case-control studies and cohort studies were 0.83 (95% CI, 0.72-0.95) and 0.93 (95% CI, 0.86-1.01), respectively. There was heterogeneity among case-control studies (P<.001) but not among cohort studies. A significant inverse association was found between fish intake and rectal cancer (summary OR, 0.79; 95% CI, 0.65-0.97), and there was a modest trend seen between fish consumption and colon cancer (summary OR, 0.96; 95% CI, 0.81-1.14). This study had no publication bias.
  
  
  CONCLUSIONS
  Our findings from this meta-analysis suggest that fish consumption is inversely associated with colorectal cancer.
authors.affiliation: Department of Psychology, Fourth Military Medical University, Xi'an, China.
authors.forename: Shengjun
authors.initials: S
authors.lastname: Wu
authors.forename: Bin
authors.initials: B
authors.lastname: Feng
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.forename: Xia
authors.initials: X
authors.lastname: Zhu
authors.forename: Shuhui
authors.initials: S
authors.lastname: Liang
authors.forename: Xufeng
authors.initials: X
authors.lastname: Liu
authors.forename: Shuang
authors.initials: S
authors.lastname: Han
authors.forename: Biaoluo
authors.initials: B
authors.lastname: Wang
authors.forename: Kaichun
authors.initials: K
authors.lastname: Wu
authors.forename: Danmin
authors.initials: D
authors.lastname: Miao
authors.forename: Jie
authors.initials: J
authors.lastname: Liang
authors.forename: Daiming
authors.initials: D
authors.lastname: Fan
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000517:prevention & control; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D015986:Confounding Factors, Epidemiologic; D005247:Feeding Behavior; D005399:Fishes; D006801:Humans; D016017:Odds Ratio; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000517:prevention & control