Seasonality of birth in patients with childhood Type I diabetes in 19 European regions

A population-based incidence cohorts of children diagnosed with Type I diabetes under 15 years of age from 1989 onwards were analysed. Previously reported data sets from Great Britain were also included together with data on children diagnosed over an additional 5 year period (1988-1992). Outside of Great Britain, no seasonality of birth was seen for any single or combination of European countries. Significant sinusoidal patterns were observed in Scotland, Yorkshire and Leicester, although the peak for Leicester appeared around autumn rather than spring. There was little evidence that sex or age at diagnosis played a part in differences in seasonal patterns, either overall or for any individual country. This study provides no consistent evidence that environmental factors, which vary from season to season, have any influence on the fetal or neonatal life to determine the onset of Type I diabetes.