title: Alcohol Consumption and the Risk of Type 2 Diabetes: A Systematic Review and Dose-Response Meta-analysis of More Than 1.9 Million Individuals From 38 Observational Studies.
abstract: OBJECTIVE
  Observational studies indicate that moderate levels of alcohol consumption may reduce the risk of type 2 diabetes. In addition to providing an updated summary of the existing literature, this meta-analysis explored whether reductions in risk may be the product of misclassification bias.
  
  
  METHODS
  A systematic search was undertaken, identifying studies that reported a temporal association between alcohol consumption and the risk of type 2 diabetes. No restrictions were placed upon the language or date of publication. Non-English publications were, where necessary, translated using online translation tools. Models were constructed using fractional polynomial regression to determine the best-fitting dose-response relationship between alcohol intake and type 2 diabetes, with a priori testing of sex and referent group interactions.
  
  
  RESULTS
  Thirty-eight studies met the selection criteria, representing 1,902,605 participants and 125,926 cases of type 2 diabetes. A conventional noncurrent drinking category was reported by 33 studies, while five reported a never-drinking category. Relative to combined abstainers, reductions in the risk of type 2 diabetes were present at all levels of alcohol intake <63 g/day, with risks increasing above this threshold. Peak risk reduction was present between 10-14 g/day at an 18% decrease in hazards. Stratification of available data revealed that reductions in risk may be specific to women only and absent in studies that adopted a never-drinking abstention category or sampled an Asian population region.
  
  
  CONCLUSIONS
  Reductions in risk among moderate alcohol drinkers may be confined to women and non-Asian populations. Although based on a minority of studies, there is also the possibility that reductions in risk may have been overestimated by studies using a referent group contaminated by less healthy former drinkers.
authors: Research Department of Epidemiology and Public Health, University College London, London, U.K. craig.knott.10@ucl.ac.uk.
authors: Craig
authors: C
authors: Knott
authors: Research Department of Epidemiology and Public Health, University College London, London, U.K.
authors: Steven
authors: S
authors: Bell
authors: Research Department of Epidemiology and Public Health, University College London, London, U.K.
authors: Annie
authors: A
authors: Britton
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology / Q000378:metabolism*; D001786:Blood Glucose / Q000187:drug effects; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000378:metabolism* / Q000517:prevention & control*; D000431:Ethanol / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D001786:Blood Glucose; D000431:Ethanol