Objective: To investigate the relationship between daily alcohol consumption and the risk of type 2 diabetes in a large Japanese cohort.
Research design and methods: We enrolled 6,362 Japanese men aged 35-61 years who did not have diabetes, impaired fasting glucose, hypertension, or liver cirrhosis at study entry. Type 2 diabetes was defined as a fasting plasma glucose (FPG) level > or =126 mg/dl or was diagnosed by a physician. Data on alcohol consumption were obtained from questionnaires. We confirmed 456 cases of type 2 diabetes during the 62,016 person-years of follow-up.
Results: The relationship between daily alcohol consumption and the risk of type 2 diabetes among lean men and among men with a higher BMI was paradoxical. Among lean men (BMI < or =22.0 kg/m2), heavy drinking was associated with an increased risk of type 2 diabetes. Men who consumed > or =50.1 ml/day of alcohol had a relative risk (RR) of 2.48 (95% CI 1.31-4.71) compared with nondrinkers after adjusting for age, BMI, regular physical exercise, parental history of diabetes, smoking habits, and FPG level. However, among men with a BMI > or =22.1 kg/m2, moderate drinking (29.1-50.0 ml/day) was associated with a decreased risk of type 2 diabetes. Daily moderate drinkers had a multiple adjusted RR of 0.58 (0.39-0.87) compared with nondrinkers.
Conclusions: Among men with a BMI > or =22.1 kg/m2, moderate alcohol consumption was associated with a reduced risk of type 2 diabetes, but among lean men (BMI < or =22.0 kg/m2), heavy alcohol consumption was associated with an increased risk of type 2 diabetes.