To provide data on the incidence of IDDM in Rome and the Lazio region evaluated prospectively from 1989 to 1993 for a total of > 5 million subjects younger than 15 years.
All patients with newly discovered IDDM diagnosed between 1 January 1989 and 31 December 1993 among residents in Rome and its region were recorded. Primary ascertainment was based in diabetes clinics and specialized hospitals in the region, whereas the secondary independent source was taken from the archives of the region where patients are registered to obtain exemption from paying for medications.
We identified 330 new patients with a degree of ascertainment of 85%. Overall the incidence rate of the disease was 7.9 per 100,000 per year (95% CI 7.1–8.8). The incidence was higher in the 5- to 9-year-old age-group (10.4 per 100,000) and in winter (36.2%). The cumulative risk for the disease is on the order of 1.18 per 1,000 subjects < 15 years of age. No significant differences in incidence were observed between boys and girls. There were 14 instances of coma at diagnosis (4.3%), but hyperglycemia without ketonuria was diagnosed in 35% of patients, suggesting an early diagnosis.
Compared with the other continental Italian regions for which data are available for a single year, the IDDM incidence rate in Rome is similar. We conclude that the IDDM incidence rate in Rome and its region is comparable to that in other Southern European countries and remained stable over the 5-year observation period.