Background: Findings of past studies on the effect of drinking patterns on diabetes risk have been inconsistent.
Objective: We aimed to investigate the role of drinking frequency and usual quantity consumed in the development of type 2 diabetes.
Design: Enrolled were 1650 Japanese men without diabetes (diabetes: fasting plasma glucose ≥7.0 mmol/L, glycated hemoglobin ≥6.5%, or self-reported clinician-diagnosed diabetes). Average alcohol consumption and 12 combinations of frequency and usual quantity per drinking occasion were assessed at the baseline examination. The absolute risk and HR for the development of diabetes were calculated.
Results: During a mean follow-up period of 10.2 y, 216 individuals developed diabetes. Lifetime abstainers (n = 153) had a relatively low incidence of diabetes (9.1/1000 person-years), similar to moderate consumers (99-160 g ethanol/wk; 9.0/1000 person-years). Increasingly higher quantities of alcohol usually consumed per occasion increased the risk of diabetes regardless of drinking frequency. The lowest incidence rate of diabetes (8.5/1000 person-years) was associated with the consumption of <1 drink (<23 g ethanol) per occasion over ≥6 times/wk. Binge drinking (≥3 drinks per occasion) significantly increased the risk of future diabetes regardless of frequency (HR: 1.79; 95% CI: 1.17, 2.74) compared with <1 drink per occasion.
Conclusions: Among current drinkers, a drinking pattern of <1 drink per occasion regularly over 6 times within a week was associated with the lowest risk of developing diabetes. Usual quantity per drinking occasion was a more important determinant than was weekly drinking frequency in the association between alcohol consumption and risk of diabetes in Japanese men.