Associations between smoking and beta-cell function in a non-hypertensive and non-diabetic population. Skaraborg Hypertension and Diabetes Project

AIMS: An increased risk for Type 2 diabetes in male and female smokers has been associated with insulin resistance. However, this might also be the result of an adverse effect on the beta-cell. The aim of the present study was to examine the association between smoking and beta-cell function. METHODS: A community-based, cross-sectional observation study. In 1994, a randomized age-stratified sample of men and women aged > or = 40 years in the city of Skara, Sweden, were invited to a survey of cardiovascular risk factors. In all, 1,109 subjects participated (80%). After the exclusion of subjects with known hypertension or diabetes mellitus, 874 subjects remained to explore. Samples were drawn after an overnight fast. Lifestyle (smoking, physical activity, alcohol consumption) was assessed using a questionnaire. Insulin resistance and insulin secretion were estimated using the homeostasis model assessment (HOMA). RESULTS: Cigarette smoking men (n = 101) had a lower HOMA beta-cell value (58.1), than never-smokers (n = 158, beta-cell value 90.1, P < 0.001). The difference remained with adjustments for age, body mass index, daily alcohol intake and physical exercise habits: 25.9 (95% confidence interval (CI) 9.7-38.8, P = 0.003). Correspondingly, in men the HOMA beta-cell value was lower in current smokers than in ex-smokers (difference 24.3, 95% CI 11.1-35.2, P < 0.001). In women, no significant difference appeared in beta-cell function vs. different smoking status. There was no association between smoking status and insulin resistance. CONCLUSIONS: At least in men, smoking may interfere with beta-cell function. The prevention of Type 2 diabetes should include strategies to stop smoking.