Objective: The purpose of this study was to describe the incidence of T1D in children in Wielkopolska province (Poland) from 2006 to 2018 and compare these data with previous data recorded between 1998-2003.
Research Design: Diabetes cases were obtained through a retrospective population-based registry. Hospital inpatient records were reviewed and met the following criteria: newly diagnosed T1D age 0-14 years, residing in Wielkopolska province at the time of diagnosis, and diagnosed from 1 January 2006 to 31 December 2018. The secondary source of validation were Diabetes Outpatient Clinics located in different parts of Wielkopolska province. Incidence rates were compared with 1998-2003 cohorts.
Results: A total of 1484 case subjects were identified during the study period, and the registry was determined to be 95% complete. In study period, a significant upward trend in the incidence of T1D was observed from 9.2/100,000/year in 2006 to 30.8/100,000/year in 2018. The peak incidence of 35.2/100,000/year was recorded in 2008. The mean age-specific incidence was greatest in children aged 5-9 years 22.6/100,000/year, while lowest in those aged 0-4 years 13.7/100,000/year. In youth aged 10-14 years, the predominance in males was documented (p=0.0007). Children aged 0-4 were characterized by different seasonal pattern at diabetes onset (mostly diagnosed in spring/summer months) than individuals over age of 10 years who were diagnosed mostly during the winter and autumn months. In a 20-year period, the incidence of T1D increased 3.5-fold from 8.4/100,000/year in 1998 to 30.8/100,000/year in 2018.
Conclusions: The incidence of T1D in Wielkopolska province is increasing. The etiology of the marked increase in incidence in the polish population is unknown, however, such rapid increase in a very short period rather is associated with environmental factors than changing in genetic background. Seasonality of the disease is not a regular occurrence, which suggests increasing role of non-seasonal factors in the growing incidence.
E. Niechcial: None. M. Michalak: None. P. Fichna: None.