Is the incidence of type 1 diabetes in children and adolescents stabilising? The first 6 years of a National Register

The Irish Childhood Diabetes National Register (ICDNR) was established in 2008 to define accurately the incidence and monitor the epidemiology of type 1 diabetes (T1D) in the Irish population. Here, we report data from the first 6 years of the National Register and compare with previous national data. Prospective national incident data regarding T1D in those under 15 years resident in Ireland were collected from 2008 to 2013 and national incidence rates (IRs) calculated. Ascertainment completeness was assessed using capture-recapture methodology. The period identified 1566 new cases of T1D, ascertainment reached 96.8 % in 2013. The standardised incidence rate was 27.5 in 2008 stabilising at 28.7 and 28.8 cases /100,000/year in 2012 and 2013. There was no evidence that the incidence changed significantly in the 6-year period either overall or for each age group and gender. There was evidence of a difference in the incidence of T1D across the age groups with the overall incidence highest in the 10-14 year age category. A strong seasonal association was demonstrated. Conclusions: This study confirms Ireland as a high-incidence country for type 1 diabetes whilst demonstrating that the previous marked increase in IR from 16.3 cases/100,000/year in 1997 has not continued. Ongoing monitoring through the robust mechanism of the ICDNR is required to clarify whether this is a fluctuation or if the incidence of T1D diabetes has stopped rising in our population. Alternatively, this apparent stabilisation may reflect a shift to a later age at diagnosis