Incidence of Type 1 diabetes in children in Cáceres, Spain, during 1988-1999

Abstract

Aim: To determine the incidence of Type 1 diabetes in Cáceres in children less than 14 years of age. We tested for differences in incidence by age, sex and season at diagnosis.

Methods: All Type 1 diabetes cases with onset <14 years of age between 1988 and 1999 were recorded retrospectively. Pediatric Unit registries provided the primary source of ascertainment. The secondary independent data source was based on the registries of local Diabetic Associations, diabetes camp records and guarantee cards of blood-glucose meters. We used the capture-recapture method for ascertainment.

Results: During the 12-year period, 137 new cases of Type 1 diabetes were identified. Completeness of ascertainment was 99.2%. Average annual observed incidence was 16.8/100,000/year (95% C.I. 14.1-19.8). Age-standardised incidence (world population): 16.5/100,000/year (95% C.I. 13.9-19.6). Average annual incidence for 0-4, 5-9 and 10-13-year-old groups: 12.7/100,000 (95% C.I. 8.8-17.9), 18.2/100,000 (95% C.I. 13.7-23.8) and 19.1/100,000 (95% C.I. 14.2-25.1). The highest age-specific annual incidence rate was found in the 10-13-year age group. There was a seasonal onset pattern, with the highest incidence in autumn and winter. November was the month with the highest number of cases (22/137).

Conclusion: Cáceres has a moderately high incidence of Type 1 diabetes in children less than 14 years of age, similar to that found in other more developed and densely populated regions of Spain, and in the range of other countries of northern Europe. These data do not support the hypothesis of a decrease in the incidence of the disease from north to south over Europe.