Alcohol consumption and diabetes risk in a Chinese population: a Mendelian randomization analysis

Abstract

Aim: To assess the causality between alcohol intake, diabetes risk and related traits. Design: Mendelian randomization (MR) study. Subgroup analysis, standard instrumental variable analysis and local average treatment effect (LATE) methods were applied to assess linear and non-linear causality. Setting: China. Participants: A total of 4536 participants, including 721 diabetes cases. Findings: Carriage of an ALDH2 rs671 A allele reduced alcohol consumption by 44.63% [95% confidence interval (CI) = –49.44%, −39.37%]. In males, additional carriage of an A allele was significantly connected to decreased diabetes risk for the overall population [odds ratio (OR) = 0.716, 95% CI = 0.567–0.904, P = 0.005] or moderate drinkers (OR = 0.564, 95% CI = 0.355–0.894, P = 0.015). In instrumental variable (IV) analysis, increasing alcohol consumption by 1.7-fold was associated with an incidence-rate ratio of 1.32 (95% CI = 1.06–1.67, P = 0.014) for diabetes risk, and elevated alcohol intake was causally connected to natural log-transformed fasting, 2-hour post-load plasma glucose (β = 0.036, 95% CI = 0.018–0.054; β = 0.072, 95% CI = 0.035–0.108) and insulin resistance [homeostatic model assessment for IR (HOMA-IR] (β = 0.104, 95% CI = 0.039–0.169), but was not associated with beta-cell function (HOMA-beta). In addition, the LATE method did not identify significant U-shaped causality between alcohol consumption and diabetes-related traits. In females, the effects of alcohol intake on all the outcomes were non-significant. Conclusion: Among men in China, higher alcohol intake appears to be causally associated with increased diabetes risk and worsened related traits, even for moderate drinkers. This study found no significant U-shaped causality between alcohol consumption and diabetes-related traits.