Increasing trend of childhood type 1 diabetes in Franche-Comté (France): analysis of age and period effects from 1980 to 1998.

AIMS/HYPOTHESIS: A study was conducted by the Franche-Comté Regional Association of Private Practitioners (Union Régionale des Médecins Libéraux de Franche-Comté) to assess trends in childhood-onset Type 1 diabetes in this administrative region of France, between 1980 and 1998.

METHODS

Cases of childhood-onset Type 1 diabetes (aged 0-14 years) were retrospectively recorded with the help of general practitioners, private specialists and hospitals in the Franche-Comté and surrounding administrative regions. Incidence rates and trends during the period were analysed using Poisson regression.

RESULTS

During the 19-year study period, 308 cases of childhood-onset Type 1 diabetes were identified. The level of case ascertainment was estimated to be 80.6% (95% CI: 74.7, 87.4). The male-to-female sex ratio was 1.03. The World standardised incidence rate was 6.90/100,000. The incidence rate was 6.03 (95% CI: 4.76, 7.53) for children aged 0 to 4 years, 6.45 (95% CI: 5.23, 7.88) for children aged 5-9 years and 8.56 (95% CI: 7.18, 10.13) for those aged 10-14 years. The annual increase rate was 4.9%, continuous and regular, without any deviation. This trend did not differ according to gender or age group.

CONCLUSION/INTERPRETATION: These results confirm that the incidence and the increase rate in childhood Type 1 diabetes in France are average compared to in other European countries over an extended period of time. Furthermore, the regular and linear increase in incidence supports the hypothesis of causal environmental factors diffusing over time. The complementary data provided also illustrate the role that private practitioners may play by their implication in epidemiology and public health.