Light-to-Moderate Alcohol Consumption Is Associated With Increased Risk of Type 2 Diabetes in Individuals With Nonalcoholic Fatty Liver Disease: A Nine-Year Cohort Study

OBJECTIVE: This study explored the association between light-to-moderate alcohol consumption (LMAC) and risk of type 2 diabetes mellitus (T2DM) in individuals with nonalcoholic fatty liver disease (NAFLD). METHODS: A 9-year cohort study was performed among Chinese men who underwent their annual health checkups between 2009 and 2018. NAFLD was diagnosed based on abdominal ultrasound with exclusion of excess alcohol intake and other causes of liver disease. Logistic regression and Cox proportional regression analyses were applied to identify the risk of prevalent and incident T2DM. RESULTS: Of the 7,079 participants enrolled, 243 had T2DM at baseline and 630 developed T2DM during the 45,456 person-years follow-up. Both at the baseline and by the end of the follow-up, LMAC was associated with a decreased risk of prevalent T2DM in NAFLD-free participants but with a significantly increased risk in patients with NAFLD. LMAC was also associated with a decreased risk of incident T2DM in NAFLD-free participants. The adjusted hazard ratios (95% confidence interval) of incident T2DM were 0.224 (0.115–0.437) and 0.464 (0.303–0.710) for NAFLD-free light drinkers and NAFLD-free moderate drinkers, respectively. Nondrinking, light-drinking, and moderate-drinking patients with NAFLD all showed significantly increased risks of incident T2DM. Compared with NAFLD-free nondrinkers, the adjusted hazard ratios (95% confidence interval) of incident T2DM were 1.672 (1.336–2.092), 2.642 (1.958–3.565), and 2.687 (2.106–3.427) for nondrinking, light-drinking, and moderate-drinking patients with NAFLD, respectively. DISCUSSION: LMAC decreased the risks of prevalent and incident T2DM in NAFLD-free participants. LMAC, however, was associated with an increased risk of T2DM in patients with NAFLD (ClinicalTrials.gov number: NCT03847116).