High incidence of childhood type 1 diabetes in Liguria, Italy, from 1989 to 1998

OBJECTIVE - Assessing updated incidence of type 1 diabetes in 0- to 14-year-old children in Liguria, a Northwest region of Italy. RESEARCH DESIGN AND METHODS - Incident cases were recorded prospectively from 1989 to 1998. Incidence rates (IRs) were standardized to the 1999 world population using the direct method. The independent effect of sex, age, residence, and calendar year was estimated with Poisson regression model. The degree of ascertainment was calculated in accordance to capture/recapture method. RESULTS - During 10 full calendar years, 219 new cases of type 1 diabetes in children were diagnosed in Liguria. The standardized IR over the 10-year period was 12.56 cases per 100,000 per year (95% CI 11.0-14.3). The sex-specific IR among men and women was 14.15 and 10.88, respectively. The age-specific IR was higher in the 10- to 14-year-old age-group (15.01/100,000) than in 0- to 4-year-old age-group (9.01/100,000) and in the 5- to 9-year-old age-group (13.03/100,000). CONCLUSIONS - The IR of type 1 diabetes in Liguria is among the highest in Southern Europe and approaches IRs of Northern European countries. In particular it is much higher than those reported in the surrounding Italian regions except for Sardinia. Therefore, the geographical distribution of type 1 diabetes does not seem to reflect the simple North-South gradient reported in several previous works.