Smoking is associated with an increased risk of type 2 diabetes but a decreased risk of autoimmune diabetes in adults: an 11-year follow-up of incidence of diabetes in the Nord-Trondelag study

Aims/hypothesis. We compared the association between smoking habits and later occurrence of type 2 diabetes on the one hand and between smoking and diabetes with autoimmunity on the other hand. Methods. We used data from a prospective study of 11-year cumulative incidence of diabetes in the Nord-Trondelag Health Survey. Results. Confirming previous reports, heavy smoking (greater than or equal to20 cigarettes per day) carried an increased relative risk (RR) of type 2 diabetes (n=738, RR=1.64, 95% Cl: 1.12-2.39). In contrast, smoking reduced the risk of latent autoimmune diabetes in adults (LADA) and of traditional type 1 diabetes (LADA n=81, RR=0.25, 95% CI: 0.11-0.60; type 1 diabetes, n=18, RR=0.17, 95% Cl: 0.04-0.73). Conclusions/interpretations. The results indicate that nicotine influences autoimmune processes in human diabetes.