Associations of Alcohol Consumption with All-Cause and Cancer Mortalities in Patients with Type 2 Diabetes Mellitus: A Nationwide Population Cohort Study.

Background: To investigate the impact of alcohol consumption on all-cause and cancer mortalities in patients with type 2 diabetes (T2D).

Methods: This nationwide cohort study included Korean patients with T2D aged >20 years from a national health exams cohort (2009 to 2012). Participants were categorized based on alcohol consumption: non, mild (<30 g/day), and heavy drinkers (≥30 g/day). Primary outcomes were all-cause and cancer mortality rates. Cox proportional hazard regression analyses were used to calculate adjusted hazard ratios (aHRs) with a 95% confidence interval (CI) with adjustments for age, sex, body mass index, smoking, exercise, comorbidities, diabetes duration, and medications.

Results: Among 2,642,359 participants (median follow-up, 7.8 years), 57.2%, 32.7%, and 10.1% were non, mild, and heavy drinkers, respectively. Compared to non-drinkers, mild alcohol consumption was associated with reduced all-cause mortality (aHR, 0.81; 95% CI, 0.80 to 0.82) and cancer mortality (aHR, 0.88; 95% CI, 0.86 to 0.89), while heavy drinking increased both all-cause (aHR, 1.06; 95% CI, 1.04 to 1.07) and cancer mortalities (aHR, 1.09; 95% CI, 1.06 to 1.11). Subgroup analyses revealed variations: in chronic kidney disease and older age groups, heavy drinkers showed lower risk of all-cause mortality compared to non-drinkers. Regarding cancer mortality, younger and middle-aged groups showed protective effects of alcohol even for heavy drinkers, while females showed linear association between alcohol consumption and cancer mortality.

Conclusion: This study indicates a J-shaped relationship between alcohol consumption and all-cause and cancer mortality risk in patients with T2D, with variations across subgroups. These findings suggest the need for personalized recommendations considering individual risk factors.