Objectives: To determine the incidence and prevalence of type 1 diabetes in children younger than 15 yr in the Autonomous Community of Castilla-Leon (Spain).
Research design and methods: All type 1 diabetic cases with onset at <15 yr of age were recorded during 2003-2004. Identified case subjects were ascertained from several sources and the capture-recapture method was used to estimate the completeness of ascertainment. For prevalence, all patients younger than 15 yr with type 1 diabetes at the beginning and at the end of the study were identified.
Results: Over the study period, 130 children aged 0-14 yr were diagnosed with type 1 diabetes. The average observed incidence of type 1 diabetes in this population was 22.22/100 000/yr (95% CI 14.57-29.81). Age-standardized incidence was 22.01/100 000/yr (95% CI 18.18-25.83). The highest incidence was observed in the 5-9 yr age-group (32.45/100 000/yr, 95% CI 24.31-40.59). The prevalence at the beginning and at the end of the study was 1.01/1000 and 1.18/1000, respectively.
Conclusion: Castilla-Leon appears to have one of the highest incidences of childhood type 1 diabetes in Spain, with recent incidence approaching those of some northern European countries.