ORIGINAL ARTICLE Type 1 diabetes incidence and prevalence trends in a cohort of Canadian children and youth Danya A Fox 1 | Nazrul Islam 2,3,4 | Jenny Sutherland 5 | Kim Reimer 5 | Shazhan Amed 1 1 Department of Pediatrics, University of British Columbia, Vancouver, Canada 2 School of Population and Public Health, Faculty of Medicine, University of British Columbia, Vancouver, Canada 3 Clinical Prevention Services, British Columbia Centre for Disease Control, Vancouver, Canada 4 Harvard T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts 5 BC Ministry of Health, Population Health Surveillance & Epidemiology, Victoria, Canada Correspondence Shazhan Amed, Department of Pediatrics, University of British Columbia, K4-206, 4480 Oak Street, Vancouver, BC, Canada V6H 3V4. Email: samed@cw.bc.ca Background and Objective: Incidence rates of type 1 diabetes have long been on the rise across the globe, however, there is emerging evidence that the rate of rise may be slowing. The objective of this study was to describe trends in the incidence and prevalence of type 1 diabetes in a sample of Canadian children and youth. Methods: Cases were extracted using linked administrative datasets and a validated diabetes case-finding definition. Incidence and prevalence trends were analyzed using the JoinPoint regression analysis program. Results: A small increase in the incidence of type 1 diabetes was observed over the 11-year period from 2002-2003 to 2012-2013. Total incident cases per year ranged from 201 (2005- 2006) to 250 (2007-2008). Total prevalent cases per year ranged from 1790 (2002-2003) to 2264 (2012-2013). Incidence was highest among children aged 5 to 14 years, and lowest in the youngest (1-4 years) and oldest (15-19 years) age brackets. The most significant increase in incidence was in children aged 10 to 14 years. Age-standardized prevalence increased signifi- cantly throughout the study period. Conclusion: These results are similar to data from the United States but differ from European data with respect to the annual percent change for incidence as well as age-specific incidence trends. In keeping with the low mortality rates associated with type 1 diabetes, the prevalence continues to rise. KEYWORDS epidemiology, pediatrics, trends, type 1 diabetes 1 | INTRODUCTION Type 1 diabetes affects over half a million children <15 years of age worldwide. Epidemiologic trends differ across geographic regions; Canada ranks 8th among countries with the highest incidence of type 1 diabetes, surpassing the United States which ranks 10th. 1 Despite Canada's high incidence rate (IR), there is limited data on incidence and prevalence trends for type 1 diabetes in Canadian children and youth. Several international registries have documented increasing rates of type 1 diabetes including DIAMOND (worldwide), EURODIAB (Europe) and SEARCH (United States) with an annual increase in inci- dence of 2.8% (95% confidence interval [CI] 2.4%-3.2%), 3.5% (95% CI 2.9%-4.1%), and 2.72% (95% CI 1.18%-4.28%), respectively. 1–4 However, in recent years, countries with the highest incidence of type 1 diabetes (eg, Sweden, Ireland, Norway, and Finland) have reported stable or declining IRs. 2,5–8 Though EURODIAB continues to report increasing IRs, more recent data suggests this rate of rise may be slowing. 3 While prevalence trends are helpful for health care resource planning, data on type 1 diabetes are scarce. SEARCH found an increase in prevalence of 21.1% over 8 years. 9 The objective of this study was to describe trends in the inci- dence and prevalence of type 1 diabetes in a sample of Canadian children and youth in the province of British Columbia. 2 | METHODS 2.1 | Data source The patient sample was extracted from administrative datasets within the Canadian province of British Columbia. These datasets exist as Received: 10 April 2017 Revised: 14 July 2017 Accepted: 17 July 2017 DOI: 10.1111/pedi.12566 © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Pediatric Diabetes. 2017;1–5. wileyonlinelibrary.com/journal/pedi 1