HETEROGENEITY OF TYPE-1 DIABETES AT ONSET IN CHILDREN - RESULTS FROM THE FRENCH INCIDENCE STUDY

Objective - The aim of this survey was to identify specific relationsh ips 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 countr y the incidence rate of the disease is low. Research design and Method s - A prospective study of the incidence of Type 1 diabetes has been s et up in four regions of France since 1988 (2.3 million inhabitants un der 20 years of age) where the epidemiological characteristics of the children have been studied as well as presentation at diagnosis. Resul ts - Five hundred and twenty one cases of newly diagnosed Type 1 diabe tes were identified over the 3 years of the study in subjects aged 0-1 9 yr. The mean incidence rate was 7.6/10(5) per year. Eighty-two perce nt 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 les s-than-or-equal-to 18 mmol/l. Islet cell antibodies and insulin auto-a ntibodies were found in 86 % and 41 % of the children, respectively. I nsulin auto-antibody positivity was significantly more frequent in the younger age group (0-4 vr : 78 %, p = 0.000 1) but not so for islet c ell antibodies. HLA-DR3/DR4 phenotype was found in 32 % of the childre n, and 11 % carried none of these antigens, irrespectively of age. DR3 phenotype was significantly associated with a lesser frequency of isl et cell antibodies (p < 0.001), but no other immunogenetic marker was associated to any clinical feature studied at presentation. Conclusion s - France is a country with a low incidence rate of Type 1 diabetes w ithin Europe. The heterogeneity of the risk for Type 1 diabetes across this continent has recently been confirmed. The variability of the ri sk according to age has also been shown in many parts of the world. Yo ung age is an important factor for severity at presentation, but immun ogenetics do not seem to play a major role in the heterogeneity of the picture at diagnosis.