High incidence of IDDM over 6 years in Edmonton, Alberta, Canada.

Objective: To determine the incidence of IDDM among children 0-14 years of age in Edmonton, Alberta, between 1990 and 1995 by means of a population-based registry.
Research Design and Methods: Children < 15 years of age diagnosed with IDDM between January 1990 and December 1995 were registered according to criteria of the World Health Organization (WHO) Multinational Project for Childhood Diabetes. The primary source of case ascertainment consisted of office records of pediatricians and endocrinologists. The secondary source consisted of inpatient records from the main city hospitals.
Results: Between 1990 and 1995, 211 IDDM patients < 15 years of age were detected by the two sources. All but 15 of them were of European ancestry. The ascertainment-corrected incidence rates of this ethnic group (constituting 77% of the population) for the 6 years were 38.6, 23.5, 23.3, 24.2, 22.0, and 24.3 per 100,000, respectively, with case ascertainment rates of 75-95%. The age-adjusted rate over the 6-year period was 25.7 per 100,000 with a case ascertainment rate of 84.3%. No sex difference was observed. The highest incidence occurred in the 10- to 14-year-old age-group, and more cases were detected between January and March than at other periods in the year.
Conclusions: The incidence of IDDM among the European-derived population in Edmonton between 1990 and 1995 is the highest rate over a 6-year period to be reported in North America, comparable to that in Prince Edward Island, Canada, and to the highest rates in the world.