Introduction: Studies carried out over the last few years have provided information about the increase in the incidence of type 1 diabetes in different parts of the world including the European countries bordering Poland.
The aim of study: The aim of this study was to determine the long-term trends in the incidence of type 1 diabetes over the 20 years between 1980 and 1999 and to compare the incidence during the decades preceding and following the 1989 economic and political transformation in Poland.
Material and methods: The registration of type 1 diabetes among people aged 0-29 was drawn up according to the DERI recommendations using three data sources. We calculated the age-standardised incidence rates for five-year age groups and determined the long-term trend in the incidence of type 1 diabetes in south-eastern Poland.
Results: A significant growth in the incidence of type 1 diabetes was observed among people aged 0-29 in the Rzeszów Province in the period between 1980 and 1999. The mean age-standardised incidence rate was 6.1/100 000, and a statistically significant difference was noted between the 1980s and the 1990s (5.3 [95%CI 4.5-6.0] and 6.8 [95%CI 5.9-7.6]). The male incidence of 6.7 significantly exceeded that for females - 5.5/100 000. There was also a higher in-cidence in the group aged 0-14 in comparison with the group aged 15-29 (6.4 and 5.8/100 000 respectively). The highest incidence was found in boys aged 10-14 (11.5/100 000) and a significantly rising trend was observed in children of 0-4 years old.
Conclusions: The mean incidence of type 1 diabetes among the study population was low. Nevertheless, we demonstrated a significantly increasing trend in the incidence during the 20-year observation period. The incidence in the 1990s, both in general and for males, was significantly higher when compared to the 1980s.