Alcohol-induced impaired insulin secretion in a Japanese population: Five-year follow-up in the Gifu Diabetes Study.

AIMS/INTRODUCTION: While moderate alcohol consumption lowers the risk of type 2 diabetes in European populations, the same cannot be assumed for Japanese patients with diabetes related to low insulin secretion rather than resistance. We aimed to evaluate the effects of daily alcohol consumption on glucose tolerance and diabetes development risk in Japanese populations.

MATERIALS AND METHODS: This retrospective study randomly enrolled 452 men and 659 women aged 40-78 years in 2005 (Gifu, Japan). The participants completed a 75-g oral glucose tolerance test and medical questionnaire. The homeostasis model assessment of insulin resistance (HOMA-R), β-cell function (HOMA-β), and insulinogenic index were used to estimate insulin sensitivity and secretion. The relationships between alcohol consumption and these parameters were analyzed using logistic regression after adjusting for potential confounders. The 5-year changes in hemoglobin A1c (HbA1c) levels were also evaluated.

RESULTS: The adjusted odds ratios for elevated HOMA-β values (<40%) in the 0-19.9 g/day, 20.0-39.9 g/day, and ≥40 g/day alcohol consumption groups were 0.98, 1.46, and 2.68, respectively. Alcohol consumption induced a significant decrease in the insulin secretion level among the ≥40 g/day drinkers, especially in men. However, there was no risk of increased insulin resistance based on the HOMA-R (<2.5) results. The 5-year risk of elevated HbA1c levels (≥ 6.5%) was increased according to increase in alcohol consumption in both men and women.

CONCLUSIONS: Daily alcohol consumption was associated with reduced insulin secretion and an increased diabetes development risk in Japanese populations.