Increasing Incidence of Type 1 and Type 2 Diabetes Among Canadian Children

Background: Diabetes mellitus is one of the most common pediatric chronic illnesses. Although a rising incidence of childhood type 1 diabetes (T1D) has frequently been documented, an almost 400-fold variation in incidence has been seen worldwide. We aimed to describe the trends in incidence of dia-betes (type 1, type 2, all types) among children and adolescents living in the Greater Montreal area of Quebec, Canada. Methods: Using health administrative data (Quebec Integrated Chronic Disease Surveillance System) and medical records from the 3 major pediatric diabetes centres in the Greater Montreal area, we conducted serial cross-sectional studies of children aged 1 to 15 years during the period from 2002 to 2010. We conducted a trend analysis of diabetes incidence over time using multivariate Poisson regression models. Results: We identified 696 new cases of diabetes between 2002 and 2010. The age-standardized inci-dence of diabetes (all types) increased from 16.3 (95% confidence interval [CI], 12.4 to 21.2) to 27.8 (95% CI, 22.5 to 34.0) per 100,000, with annual incidence increasing, on average, by 5.2% per year (adjusted rate ratio [aRR], 1.052; 95% CI, 1.022 to 1.083). This was driven predominantly by the T1D annual increase of 5.4% (aRR, 1.054; 95% CI, 1.023 to 1.086). A low number of incident cases of type 2 diabetes limited trend analysis in this group. There were no significant interactions between year and sex or age. Conclusions: The annual incidence of T1D is increasing in Quebec children and does not vary by sex or age. Further research into etiologic factors is indicated.(c) 2021 Canadian Diabetes Association.