The relationship between alcohol consumption, body mass index and type 2 diabetes: A systematic review and dose-response meta-analysis

Background: Moderate alcohol use may be associated with lower risk of type 2 diabetes (T2DM). Previous reviews have reached mixed conclusions.

Purpose: Quantify the dose-response relationship between alcohol consumption and T2DM, accounting for differential effects by sex and BMI.

Data Sources: Systematic review searching Medline, Embase, Web of Science, and one secondary data source.

Study Selection: Cohort studies on the relationship between alcohol use and T2DM.

Data Extraction: 55 studies, and one secondary data source, were included with a combined sample size of 1,363,355 men and 1,290,628 women, and 89,983 and 57,974 cases, respectively.

Data Synthesis: Multivariate dose-response meta-analytic random-effect models were used. For women, a J-shaped relationship was found with a maximum risk reduction of 31% (RR 0.69, 95% CI 0.64-0.74) at an intake of 16 grams of pure alcohol per day compared to lifetime abstainers. The protective association ceased above 49 grams per day (RR 0.82, 95% CI 0.68-0.99). For men, no statistically significant relationship was identified. When stratifying by BMI, the protective association was only found in overweigh and obese women.

Limitations: Our analysis relied on aggregate data, we included some papers that determined exposure and cases via self-report and the studies did not account for temporal variations in alcohol use.

Conclusions: The observed reduced risk seems to be specific to women in general and women with a BMI above 25 kg/m2. Our findings allow for a more precise prediction of the sex-specific relationship between T2DM and alcohol use as our results differ from previous studies.