Incidence of IDDM in Western Australia in children aged 0-14 yr from 1985 to 1989.

OBJECTIVE

To document the incidence of insulin-dependent diabetes mellitus (IDDM) in Western Australia in children aged 0-14 yr between 1985 and 1989 and to test for differences in incidence by year of diagnosis, age of diagnosis, and sex.

RESEARCH DESIGN AND METHODS

A population-based register that used a primary source of case ascertainment (diabetes clinics at teaching hospitals and direct approach to general practitioners and general physicians) and a secondary source (Western Australian Hospital Morbidity Data System) established numerator data. Denominator data were obtained from the Australian Bureau of Statistics.

RESULTS

From 1985 to 1989 inclusive, 235 children in the 0- to 14-yr age-group were diagnosed with IDDM in Western Australia. Case ascertainment was estimated at 99% complete. The mean age-adjusted (developed-world population) annual incidence of IDDM was 13.2 per 100,000 person-yr and there was no evidence of an increasing incidence over the 5 yr. However, girls were more likely than boys to be diagnosed with IDDM in this period (P = 0.006).

CONCLUSIONS

The incidence of IDDM in Western Australia is in the middle range of IDDM incidence in countries throughout the world. The unexpected finding of an increased incidence of IDDM in girls compared with boys needs to be confirmed in a future study.