Aims/hypothesis: The incidence rate of childhood-onset Type I (insulin-dependent) diabetes mellitus in Slovenian children during the period 1990-1998 was studied and compared to that of children from the Tuzla region (Bosnia and Herzegovina). The secular trend for a 25-year period in Slovenia was also investigated.
Methods: The incidence data were obtained from the national Slovenian Type I diabetes register and from the local Type I diabetes register held in Tuzla. The ascertainment was based on the capture-recapture method and was estimated to be 100%.
Results: The age-standardized incidence of Type I diabetes mellitus for the age group 0-14 years for Slovenia was 8.54 per 100,000 (95 %-C.I. 7.5-9.5) person-years for both sexes. The incidence for boys was 8.03 per 100,000 (95 %-C.I. 6.7-9.4) and 9.12 per 100,000 (95% -C.I. 7.6-10.6) for girls. The age-standardized incidence in the Tuzla region was much lower: 3.03 per 100,000 (95 %-C.I. 2.0-4.1) for the whole group, 3.44 per 100 000 (95 %-C.I. 1.8-5.0) for boys and 3.21 per 100,000 (95 %-C.I. 1.6-4.7) for girls. A very low incidence of 0.8 per 100,000 in the youngest age group (0-4 years) was observed in the Tuzla region. The linear trend of the Type I diabetes incidence rate in Slovenia has been steadily increasing by 3.6% per year for the last 25 years. The incidence rate in the period 1974-1985 was significantly lower than that in the period 1986-1998 (p < 0.00026).
Conclusions/interpretation: Although the incidence rate in Slovenia slightly increased during the period 1990-1998, the incidence rate in the Tuzla region remained at the pre-war level.