title: Diabetes mellitus and incidence and mortality of gastric cancer: a meta-analysis.
abstract: OBJECTIVE
  Epidemiologic studies have examined the possible associations between diabetes mellitus (DM) and gastric cancer (GC), but the results are inconclusive. We conducted a meta-analysis to assess the evidence regarding the associations between diabetes and incidences of, or mortality from, gastric cancer.
  
  
  METHODS
  PubMed, Embase and Web of Science were searched up to Oct 20, 2011. We identified studies that included effects estimates with 95% confidence intervals (CIs) of the associations between GC and diabetes. Summary RRs for the GC incidence and mortality were calculated using random-effects model; subgroup analyses were also performed. Heterogeneity among studies was examined using Q and I2 statistics.
  
  
  RESULTS
  A total of 7 case-control and 18 cohort studies met the inclusion criteria. The summary RR showed a slightly statistical link between history of DM and GC incidence (RR=1.11, 95% CI: 1.00-1.24, p=0.045, I2=79.5%). In the subgroup analyses, a positive association was noted among the studies conducted in Asia (summary RR=1.19, 95% CI: 1.07-1.32, I2=29.8%). Additionally, slight associations between DM and GC were observed by pooling the data of type 2 DM, cohort studies and the studies controlling more confounders, respectively. Furthermore, mortality from GC with diabetes was increased compared with individuals without diabetes (summary RR=1.29, 95% CI: 1.04-1.59). No publication bias was found.
  
  
  CONCLUSIONS
  Individuals with diabetes have an increased risk of developing gastric cancer, and are positively associated with gastric cancer mortality. Large better-designed cohort studies are needed to verify this conclusion.
authors.affiliation: Department of Endocrinology, the First Affiliated Hospital of Nanjing Medical University, China.
authors.forename: T
authors.initials: T
authors.lastname: Tian
authors.forename: L Q
authors.initials: LQ
authors.lastname: Zhang
authors.forename: X H
authors.initials: XH
authors.lastname: Ma
authors.forename: J N
authors.initials: JN
authors.lastname: Zhou
authors.forename: J
authors.initials: J
authors.lastname: Shen
mesh_terms: D015982:Bias; D016022:Case-Control Studies; D015331:Cohort Studies; D048909:Diabetes Complications / Q000453:epidemiology / Q000401:mortality; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000401:mortality; D006801:Humans; D015994:Incidence; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000401:mortality*; D016019:Survival Analysis