The rising incidence of childhood type 1 diabetes in New South Wales, Australia

OBJECTIVES: 1. To determine the incidence of type 1 (insulin dependent) diabetes in children aged 0-14 years who were resident in the state of New South Wales, Australia over the period 1992-1996. 2. To analyse the trends in incidence over the period 1990-1996. METHODS: Primary ascertainment of patients was performed using a prospective incidence register established in 1990. The secondary source of ascertainment was the National Diabetes Supply Scheme, a government subsidised scheme for diabetic supplies. RESULTS: There were 1,230 patients identified over the five-year period. Using the capture-recapture method, ascertainment was estimated to be 99% complete. The lowest incidence occurred in 1992 (16.9 per 10(5) person years) and the highest incidence was in 1995 (21.7 per 10(5)). The crude incidence of IDDM from 1990-1996 was 17.8 per 10(5) and there was a statistically significant rise in the incidence of type 1 diabetes over this period (p=0.0003). The annual incidence has increased on average by 3.2% per year since 1990. CONCLUSION: The incidence of childhood type 1 diabetes in NSW has increased significantly since 1990.