Dose-Response Association between Alcohol Consumption and Kidney Cancer Risk Differs According to Glycemic Status: A Nationwide Cohort Study of 9.4 Million Individuals.

Purpose: Previous studies suggested an association between alcohol consumption and reduced kidney cancer risk. Given a potential interaction between alcohol's insulin-sensitizing effect and hyperglycemia-related insulin resistance, we aimed to assess whether the dose-response association between alcohol intake and kidney cancer risk varies based on glycemic status.

Materials and methods: This nationwide cohort study analyzed data from 9,492,331 adults who underwent a national health screening program in 2009 and were followed until 2018. Multivariable-adjusted Cox regression models were applied to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

Results: Over a median follow-up period of 8.3 years, 12,381 participants were diagnosed with kidney cancer. A U-shaped relationship between alcohol consumption and kidney cancer risk was observed among individuals with normoglycemia (light-to-moderate: HR, 0.94; 95% CI, 0.89 to 0.99 and heavy: HR, 1.00; 95% CI, 0.91 to 1.09, respectively). In prediabetic individuals, alcohol consumption was not significantly associated with kidney cancer risk. In individuals with diabetes, a dose-dependent increase in kidney cancer risk was noted with higher alcohol consumption (light-to-moderate consumption: HR, 1.12; 95% CI, 1.03 to 1.22; heavy consumption: HR, 1.24; 95% CI, 1.09 to 1.42; p for trend < 0.01).

Conclusion: A modest U-shaped dose-response association between alcohol consumption and kidney cancer risk was observed exclusively in individuals with normoglycemia. Individuals with diabetes demonstrated a dose-dependent increased risk of kidney cancer with higher alcohol consumption. Tailored patient education and personalized risk assessments regarding alcohol consumption and kidney cancer risk should be emphasized over a generalized 'one-size-fits-all' approach.