title: Association between zinc intake and risk of digestive tract cancers: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Association between zinc intake and digestive tract cancers risk has been reported in several epidemiological studies, while the results were controversial. The aim of our study was to get a systemic review of this issue.
  
  
  METHODS
  PUBMED and EMBASE were searched up to April 2013, supplemented with manual-screening for relevant articles. Two independent reviewers independently extracted data from eligible studies, risk ratio (RR) or odds ratio (OR) with 95% CIs for the highest versus lowest categories of zinc intake was adopted. Either a fixed- or a random-effects model was adopted to estimate overall odds ratios. Besides, dose-response, subgroup, and publication bias analyses were applied.
  
  
  RESULTS
  Nineteen studies with approximately 400,000 participants were included in this meta-analysis. The pooled relative risk (RR) of overall digestive tract cancers for the highest versus lowest categories of zinc intake was 0.82 (95% CI: 0.70-0.96; p = 0.013). Comparing the highest with lowest categories, higher zinc intake was significantly associated with reduced colorectal cancer risk (pooled RR = 0.80, 95% CI: 0.70-0.92; p = 0.002), while zinc intake was not statistically associated with gastric cancer risk (pooled RR = 0.91, 95% CI: 0.64-1.29; p = 0.581) or esophageal cancer risk (pooled RR = 0.72, 95% CI: 0.44-1.17; p = 0.187). However, subgroup analyses showed that zinc intake was significantly associated with esophageal cancer risk and gastric cancer risk in Asia, but not in America and Europe.
  
  
  CONCLUSIONS
  Dietary zinc intake was inversely associated with digestive tract cancers, especially colorectal cancer risk in this study.
authors.affiliation: Department of Epidemiology and Health Statistics, Zhejiang University School of Public Health, Hangzhou 310058, China.
authors.forename: Peiwei
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Epidemiology and Health Statistics, Zhejiang University School of Public Health, Hangzhou 310058, China.
authors.forename: Jinming
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Department of Epidemiology and Health Statistics, Zhejiang University School of Public Health, Hangzhou 310058, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Ye
authors.affiliation: Department of Epidemiology and Health Statistics, Zhejiang University School of Public Health, Hangzhou 310058, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Chen
authors.affiliation: Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Zhejiang University, Hangzhou 310003, China; Department of Biomedicine, Zhejiang Agriculture and Forestry University School of Biotechnology, 88 Huan Cheng Bei Road, Lin An, Zhejiang 311300, China. Electronic address: gastate@zju.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Epidemiology and Health Statistics, Zhejiang University School of Public Health, Hangzhou 310058, China. Electronic address: georgewuer@126.com.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Wu
mesh_terms: D015179:Colorectal Neoplasms / Q000517:prevention & control*; D004032:Diet; D019587:Dietary Supplements; D004938:Esophageal Neoplasms / Q000517:prevention & control*; D006801:Humans; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000517:prevention & control*; D015032:Zinc / Q000008:administration & dosage*
chemical_list: D015032:Zinc
keywords: Digestive tract cancers; Meta-analysis; Zinc