Incidence of type 1 diabetes in Sardinian children aged 0–14 years has almost doubled in the last twenty years. On top of the world

Aims: The primary objectives were to investigate the incidence rate (IR) of type 1 diabetes (T1D) in Sardinian children aged 0-14 years in 2019-2022 and to examine the temporal trend from 1989-1999. Methods: Data from new-onset T1D patients aged 0-14 years who were residents of Sardinia were collected from all pediatric diabetology clinics. The overall, sex- and age specific (groups 0-4, 5-9, and 10-14 years), and calendar year IRs were calculated. The standardized IR (SIR) was also calculated using the direct method. Poisson regression was used to estimate the temporal trend in the SIRs from 1989-1999 to 2019-2022. Results: In 2019-2022, 512 patients aged 0-14 years were diagnosed with T1D in Sardinia. The overall IR was 73.9 per 100,000 person-years (95 % CI 67.6-80.0). Since 1989, the SIR has increased by 2.3 % per year (CI 1.7-2.8, p < 0.0001). The frequency of ketoacidosis at onset was 26.4 %, with no significant differences among the four years. Conclusions: The incidence of T1D in Sardinia, unlike in other countries such as Finland, has almost doubled in the last 20 years, and currently, it appears to be the highest in the world.