Smoking and incidence of diabetes among US adults: Findings from the Insulin Resistance Atherosclerosis Study

OBJECTIVE - The objective of this study was to determine the association between smoking and incident diabetes among U.S. adults. RESEARCH DESIGN, AND METHODS - The insulin Resistance Atherosclerosis Study (IRAS) was a prospective study of the associations of insulin sensitivity and cardiovascular risk factors. We examined the relationship between smoking status categories (never, former, and current) and incident 5-year type 2 diabetes among 906 participants free of diabetes at baseline. We also considered the effect of pack-year categories (never, former <20 pack-years, former >= 20 pack-years, current <20 pack-years, and current >= 20 pack-years) upon diabetes incidence. RESULTS - Of current smokers, 96 (25%) developed diabetes at 5 years, compared with 60 (14%) never smokers. After multivariable adjustment, current smokers exhibited increased incidence of diabetes compared with never smokers (odds ratio [OR] 2.66, P = 0.001). Similar results were found among current smokers with >= 20 pck-years with normal glucose tolerance (5.66, P = 0.001). CONCLUSIONS - Smoking shares a robust association with incident diabetes, supporting the current Surgeon General's warnings against cigarette smoking.