Smoking is known to be a major contributor to heart disease, yet its role in the development of diabetes has been largely overlooked. The authors searched for studies reporting the presence of impaired fasting glucose, impaired glucose tolerance, or type 2 diabetes in active smokers and narrowed their results to 25 prospective cohort studies published between 1992 and 2006. The combined population was 1.2 million participants, 35% of whom were reported smokers. During follow-up, which ranged from five to 30 years, 45,844 cases of diabetes were reported.

A positive correlation between active smoking and increased risk of diabetes was found in 24 of the 25 studies; however, not all correlations were statistically significant. Diabetes was more likely to occur in active smokers who were age 50 or older, were overweight or obese, or reported smoking 20 or more cigarettes daily. A somewhat stronger correlation was also found if diabetes was determined by biological screening rather than by patient or physician report. Inactivity, poor diet, high alcohol consumption, and low socioeconomic status, which are often associated with smoking, were also identified as possible reasons for the increased incidence of diabetes in the population.

The crux of the matter. This and other studies confirm the positive relationship between cigarette smoking and diabetes incidence. Future studies should address whether-and if so, how-active smoking causes type 2 diabetes.

Willi C, et al. JAMA 2007;298(22):2654-64.

Section Description

Evidence for Excellence is a periodic department showcasing new evidence-based practice guidelines and results of systematic literature reviews to help the nurse in practice.

Practice Guidelines

Systematic Review