INSULIN-DEPENDENT DIABETES IN CHILDREN UNDER 5 - INCIDENCE AND ASCERTAINMENT VALIDATION FOR 1992

Objective-To establish the incidence of insulin dependent diabetes dia gnosed in children under 5 years of age in the British Isles during 19 92, comparing the national and regional results with those of our 1988 national study, and estimating the 1992 study's level of case ascerta inment. Design-Active monthly reporting of cases by consultant paediat ricians through the framework of the British Paediatric Surveillance U nit, with additional reports from specialist diabetes nurses and regio nal health authorities. Subjects-All children diagnosed under the age of 5 years with primary insulin dependent diabetes from 1 January to 3 1 December 1992 (inclusive) and resident in the British Isles at diagn osis. Results-387 children (208 boys and 179 girls) were confirmed to have insulin dependent diabetes, giving a national incidence of 9 . 3/ 100 000/year. This is similar to the 9 . 9/100 000/year found in 1988. Three sample capture-recapture analysis, which could only be applied across the 12 (out of 18) regions supplying regional information to th e study, suggested ascertainment rates of 78% for the British Paediatr ic Surveillance Unit, 67% for specialist nurses, 69% for regional heal th authorities, and 99% for the aggregated registry. Conclusions-The n ational incidence of diabetes in the under 5s in the British Isles did not differ between 1988 and 1992. Nearly complete (99%) ascertainment of cases was possible only for regions for which three data sources w ere available. Capture-recapture analysis highlighted both the need fo r more than one data source and for each data source to be complete fo r the whole study area.