Objective: The aim of this survey was to identify specific relationships between clinical and biological features and immunogenetic markers at presentation in a large cohort of newly diagnosed Type 1 diabetic children recruited from the French incidence registry, in which country the incidence rate of the disease is low.
Research design and methods: A prospective study of the incidence of Type 1 diabetes has been set up in four regions of France since 1988 (2.3 million inhabitants under 20 years of age) where the epidemiological characteristics of the children have been studied as well as presentation at diagnosis.
Results: Five hundred and twenty one cases of newly diagnosed Type 1 diabetes were identified over the 3 years of the study in subjects aged 0-19 yr. The mean incidence rate was 7.6/10(5) per year. Eighty-two percent of the children had a symptomatic period shorter than or equal to 2 months. The mean weight loss was -9.2 +/- 7% of body weight. Forty-eight percent of the children demonstrated plasma total CO2 values < or = 18 mmol/l. Islet cell antibodies and insulin auto-antibodies were found in 86% and 41% of the children, respectively. Insulin auto-antibody positivity was significantly more frequent in the younger age group (0-4 yr: 78%, p = 0.0001) but not so for islet cell antibodies. HLA-DR3/DR4 phenotype was found in 32% of the children, and 11% carried none of these antigens, irrespectively of age. DR3 phenotype was significantly associated with a lesser frequency of islet cell antibodies (p < 0.001), but no other immunogenetic marker was associated to any clinical feature studied at presentation.
Conclusions: France is a country with a low incidence rate of Type 1 diabetes within Europe. The heterogeneity of the risk for Type 1 diabetes across this continent has recently been confirmed. The variability of the risk according to age has also been shown in many parts of the world. Young age is an important factor for severity at presentation, but immunogenetics do not seem to play a major role in the heterogeneity of the picture at diagnosis.