Excess body weight, cigarette smoking, and type II diabetes incidence in the national FINRISK studies

Abstract

PurposeWe identify the individual and joint contributions of excess weight and cigarette smoking to national-level type II diabetes (T2D) incidence and to educational and gender disparities therein filling an important gap in T2D epidemiology. MethodsBased on the FINRISK surveys conducted in 1997, 2002, and 2007 and linked to the Finnish National Drug Reimbursement Register through 2011, we used a regression-counterfactual approach to estimate the percentage of diagnosed drug-treated incident T2D cases attributable to excess body weight and cigarette smoking. Body mass index (BMI) and waist circumference were evaluated. ResultsT2D incidence was 10.24 in men and 7.04 in women per 1000 person-years. Excess baseline BMI (≥25.0 kg/m2) explained 69% and 63%, and smoking explained 9% and 14% of T2D incidence, in men and women, respectively. Most of the gender difference was explained by the risk factors. Approximately 90% in men and 98% in women of the higher T2D incidence among those in the lower versus upper third of the educational distribution was explained by excess BMI. The results were similar for waist circumference and lifetime maximum BMI. ConclusionsExcess body weight is the main risk factor contributing to national-level T2D incidence and disparities by educational attainment and gender in a high-income population.