IDDM IN THE PROVINCE OF PAVIA, ITALY, FROM A POPULATION-BASED REGISTRY - A DESCRIPTIVE STUDY

OBJECTIVE-To report the incidence of insulin-dependent diabetes mellit us (IDDM) in the Province of Pavia, Italy, in the 0- to 29-year-old ag e-group between 1988 and 1992. Urban versus rural residence, socioecon omic level, and family size of IDDM cases were also investigated. RESE ARCH DESIGN AND METHODS-A prospective register was established in 1988 to collect all newly diagnosed IDDM patients with onset before 30 yea rs of age. The primary data source was based on notification of new ca ses by hospitals, out-patient clinics, family doctors, and pediatricia ns. The secondary and independent data source consisted of the registr ies of prescriptions for insulin syringes in the health districts of t he province. RESULTS-In 5 years (1988-1992), 66 cases of IDDM in the 0 - to 29-year-old age-group were identified. The completeness of ascert ainment was 100% for the combined sources. Age-adjusted (world-standar dized) incidence rates per 100,000 (95% confidence interval) were 9.52 (6.42-13.61), 6.72 (4.68-9.34), and 8.27 (6.42-10.58), respectively, for the age-groups 0-14, 15-29, and 0-29. The rates were higher for re sidents in urban areas. The number of children in the families of IDDM patients was significantly higher than in the reference population. C ONCLUSIONS-Our data indicate the concordance of IDDM incidence rates w ith the North-Italian rates and a possible association of the disease with environmental factors. These factors might enhance the susceptibi lity to IDDM in genetically predisposed individuals.