Incidence of IDDM during 1984-1986 in population aged less than 30 yr. Residents of Turin, Italy.

The goal of this study was to measure the incidence of insulin-dependent diabetes mellitus (IDDM) during 1984-1986 in residents of Turin, Italy, aged less than 30 yr. The primary data source was the list of all subjects diagnosed with IDDM who attended diabetes clinics in Turin. Other data sources were the general register of death certificates, the list of hospital discharges, and the computerized data base of insulin prescriptions. Eighty incident cases of IDDM were identified during the study in 1,130,284 person-yr for those less than 30 yr of age. Age-adjusted (world standard) incidence rates were 8.05, 8.10, and 6.96/100,000 in the age-groups 0-14, 0-19, and 0-29 yr, respectively. Estimated completeness of the primary data source compared with all other data sources was 91%, whereas the estimated completeness of ascertainment of the registry was 99%. Incidence rates of IDDM in northern Italy compare with those of European countries with low-medium incidence. A population-based register is being established for the province of Turin (951,445 inhabitants aged 0-29 yr) for the collection of incident cases since 1984.