title: Consumption of vegetables may reduce the risk of liver cancer: results from a meta-analysis of case-control and cohort studies.
abstract: OBJECTIVE
  We conducted a meta-analysis of all published case-control and cohort studies to evaluate the relationship between vegetables intake and liver cancer risk.
  
  
  METHODS
  We searched for cohort and case-control studies published before February 2014, using Pubmed and Cochrane Library Central database. Pooled relative risk (RR) estimates and corresponding 95% confidence interval (CI) were calculated using the inverse-variance method.
  
  
  RESULTS
  Eight case-control studies and one cohort study were included in this meta-analysis, involving a total of 136,425 subjects and 1349 liver cancer cases. Finally, we observed a statistically significant protective effect of vegetables consumption on liver cancer (RR=0.78, 95% CI [0.62, 0.99]). In the present meta-analysis, no publication bias was observed among studies using Begg's P value (P=0.532); Egger's (P=0.180) test, which suggested there was no evidence of publication bias.
  
  
  CONCLUSIONS
  Our results suggest that vegetables consumption may reduce the risk of liver cancer. More prospective cohort studies with larger sample size, well-controlled confounding factors are warranted to further evaluate the association.
authors.affiliation: The Third Xiangya Hospital of Central South University, Changsha, China; Key Laboratory of Medical Information Research (Central South University), College of Hunan Province, Changsha, China.
authors.forename: Ai-Jing
authors.initials: AJ
authors.lastname: Luo
authors.affiliation: School of Public Health, Central South University, Changsha, China; Department of Medicine Management, Bengbu Medical College, Bengbu, China. Electronic address: bengbu_wangfuzhi@126.com.
authors.forename: Fu-Zhi
authors.initials: FZ
authors.lastname: Wang
authors.affiliation: Department of Medicine Management, Bengbu Medical College, Bengbu, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Luo
authors.affiliation: Key Laboratory of Medical Information Research (Central South University), College of Hunan Province, Changsha, China; Department of Medical Information, Center South University, Changsha, China.
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Hu
authors.affiliation: The Third Xiangya Hospital of Central South University, Changsha, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Mao
authors.affiliation: The Third Xiangya Hospital of Central South University, Changsha, China; Key Laboratory of Medical Information Research (Central South University), College of Hunan Province, Changsha, China.
authors.forename: Wen-Zhao
authors.initials: WZ
authors.lastname: Xie
authors.affiliation: School of Public Health, Central South University, Changsha, China.
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: He
authors.affiliation: School of Public Health, Central South University, Changsha, China; School of Public Management, Jiangsu University of Science and Technology, Zhenjiang, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Kan
authors.affiliation: School of Public Health, Central South University, Changsha, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D004032:Diet; D006801:Humans; D008113:Liver Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D012306:Risk; D014675:Vegetables