Moderate alcohol consumption is associated with impaired insulin secretion and fasting glucose in non‐obese non‐diabetic men

AIMS/INTRODUCTION: A low insulin secretion capacity has been implicated in the high prevalence of non‐obese diabetes in East Asians. As alcohol consumption alters insulin and glucose metabolism, we tested the hypothesis that alcohol consumption contributes to impaired insulin secretion and glucose intolerance in lean/normal‐weight non‐diabetic Japanese men. MATERIALS AND METHODS: This cross‐sectional study was undertaken among the residents of Shika town, Japan, between 2011 and 2017. A total of 402 non‐diabetic men, including participants with normal fasting plasma glucose (FPG) and impaired FPG (FPG 5.6–6.9 mmol/L), and aged ≥40 years, were examined. FPG, the homeostasis model assessment of insulin secretion capacity (HOMA‐B) and alcohol consumption were evaluated and compared between the body mass index (BMI) <25 and BMI ≥25 groups. RESULTS: HOMA‐B levels were lower in the BMI <25 group than in the BMI ≥25 group. Alcohol consumption correlated with a low HOMA‐B level regardless of BMI, and, thus, the HOMA‐B levels of alcohol drinkers were significantly lower in the BMI <25 group. A multivariable logistic regression analysis showed that alcohol consumption, even light‐to‐moderate consumption (1–25 g/day), was associated with significantly low levels of HOMA‐B and impaired FPG in the BMI <25 group. Among participants with impaired FPG, a low level of HOMA‐B was observed in alcohol drinkers, but not in non‐drinkers. In contrast, light‐to‐moderate alcohol consumption was not related to HOMA‐B or FPG in the BMI ≥25‐group. CONCLUSION: Alcohol consumption, even a small amount, might contribute to reductions in HOMA‐B levels and impaired FPG in lean/normal‐weight Japanese men.