Associations Between Alcohol Consumption and Cigarette Smoking and Insulin Secretion and Resistance in Vietnamese Men Without a History of Diabetes: A Cross‐Sectional Study

<b>Introduction:</b> This study is aimed at examining the associations of alcohol consumption and cigarette smoking with insulin secretion and resistance and the effect modification by body mass index (BMI) in middle-aged men without a history of diabetes in rural Vietnam. <b>Materials and Methods:</b> The study included data from 1102 men without diabetes, aged between 40 and 60 years, who participated in the Khánh Hòa Cardiovascular Study conducted between June 2019 and 2020. Fasting blood samples were collected to measure insulin and plasma glucose. Alcohol consumption was categorized as no consumers or consumers (< 1, 1-1.9, and ≥ 2 standard drinks per day). Smoking was categorized as never, former, and current smokers (≤ 10 or ≥ 11 cigarettes per day). The homeostatic model assessment (HOMA) was used to assess insulin secretion (HOMA-beta) and insulin resistance (HOMA-IR). A multilevel linear regression model was used to examine the associations of alcohol consumption and smoking with HOMA-beta and HOMA-IR. Effect modification by BMI was tested using the likelihood ratio test, and a set of stratified analyses according to BMI (23 kg/m²) was performed. <b>Results:</b> Alcohol consumption showed a dose-response association with low HOMA-beta in both the unadjusted and BMI-adjusted models. Cigarette smoking was not associated with HOMA-beta in either the unadjusted or BMI-adjusted models. Alcohol consumption was not associated with HOMA-IR when BMI was unadjusted, but the highest alcohol consumer group showed a significantly lower HOMA-IR after adjustment for BMI. Current smoking was significantly associated with lower HOMA-IR when BMI was unadjusted, which association became marginally significant after adjusting for BMI. <b>Conclusions:</b> Alcohol consumption was associated with reduced insulin secretion. Smoking was marginally associated with lower insulin resistance, potentially mediated by low BMI. Longitudinal studies are required to explore the mechanisms underlying the association between alcohol consumption, smoking, and glucose metabolism.