In case patients need another reason to quit smoking, this study found that smokers had a 2-5 times higher risk of developing Type 2 diabetes than nonsmokers. In other words, a current smoker has a 1 in 4 chance of developing diabetes within the next 5 years. The Insulin Resistance Atherosclerosis Study (IRAS) followed 1624 multi-ethnic subjects for over 5 years; of these, the 906 subjects free of diabetes at baseline were used for this analysis. The strengths of this prospective study include the careful determination of insulin sensitivity and cardiovascular risk factors. Despite being younger and having lower BMIs, current smokers in this study had a more than 2.7-fold higher incidence of diabetes at 5 years than nonsmokers. All levels of cigarette smoking carried an increased risk of diabetes, with similar levels of risk in those with a <20 pack-year history. These results are similar to those from the Physician’s Health and Nurse’s Health Studies. Smoking may increase the risk of diabetes through a number of mechanisms, including increased inflammation, oxidative stress, and impaired endothelial function which may result in reduced insulin sensitivity. Smoking appears to be an independent and modifiable risk factor for diabetes. --Jennifer G. Robinson, MD