[Polish multicenter study on type I diabetes incidence in the age group 15-29 between 1998 and 1999]

The increase in diabetes type 1 incidence observed in various centers in Poland and the need for a centralized study covering a large population have resulted in the construction of a standardized registry of type 1 diabetes in 1998 within the Polish Multicenter Study in Diabetes Epidemiology. The aim of the study was to evaluate the incidence of type 1 diabetes in the age group 15-29 in 5 distinct regions of Poland (Krakow, Warsaw, Bialystok, Rzeszow and Olsztyn centers) with over 15% of the Polish population at risk in 1998 and 1999. The data for the standardized registry were obtained prospectively from hospital departments and diabetes outpatient units. The incidence rates calculated in 1998 showed the highest value of 11.2/100,000 for Krakow and its region, and the lowest (4.4/100,000) for Bialystok and its region. In 1999 the highest value of 12.3/100,000 was noted in Olsztyn and its region and the lowest (3.4/100,000) in Warsaw. There were significant differences in the incidence rates between the study centers were found. Incidence rates in the whole study area were significantly higher among males as compared with females in 1998 and 1999 (8.9/100,000 vs. 4.9/100,000; p = 0.0001), marked in the age groups 15-19 and 20-24 (p = 0.001 and p = 0.002 respectively). A significant increase in diabetes type 1 incidence (from 4.6/100,000 to 6.9/100,000) was found as compared with results of the "Three Cities Study" (1986-1988).