title: Association of Helicobacter pylori infection with diabetes mellitus and diabetic nephropathy: a meta-analysis of 39 studies involving more than 20,000 participants.
abstract: BACKGROUND
  Helicobacter pylori infects more than half of the world's population. The aim of this study was to quantify the association between H. pylori infection and the risk of diabetes mellitus and diabetic nephropathy, and to detect at which stage the infection might have higher pathogenicity in the disease-free status-diabetes mellitus-diabetic nephropathy process.
  
  
  METHODS
  A literature search was performed to identify studies published between 1997 and 2012 for relative risk estimates. Fixed and random effects meta-analytical techniques were conducted for diabetes mellitus and diabetic nephropathy.
  
  
  RESULTS
  Thirty-seven case-control studies and 2 cohort studies were included. H. pylori was associated with an increased risk of each type of diabetes mellitus (odds ratio (OR) 2.00, 95% confidence interval (CI) 1.82-2.20, p for heterogeneity = 0.07). The infection was also associated with increased risks of type 1 and type 2 diabetes mellitus, separately (OR 1.99, 95% CI 1.52-2.60, p for heterogeneity = 0.15, and OR 2.15, 95% CI 1.81-2.55, p for heterogeneity = 0.24, respectively). In addition, we found a significant association between H. pylori infection and diabetic nephropathy risk (OR 1.60, 95% CI 1.10-2.33, p for heterogeneity = 0.44).
  
  
  CONCLUSIONS
  Our meta-analyses suggest a relationship between H. pylori infection and the risk of diabetes mellitus and diabetic nephropathy. The bacterium may be able to play its pathogenic role in the whole disease process, and this action may be stronger in type 2 diabetic patients than in type 1 diabetic patients.
authors.affiliation: From the Department of Internal Medicine, Tianjin Union Medicine Center and Tianjin People's Hospital.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.forename: Zongshun
authors.initials: Z
authors.lastname: Lv
mesh_terms: D048909:Diabetes Complications / Q000382:microbiology*; D003928:Diabetic Nephropathies / Q000382:microbiology*; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori / Q000302:isolation & purification* / Q000472:pathogenicity; D006801:Humans; D016017:Odds Ratio