Increased incidence of pediatric type 1 diabetes during the pandemic in Biscay, Spain

Objective: To update the incidence rate (IR) and trends of type 1 diabetes mellitus (T1DM) in children aged 0-14 years from 2003 to 2022, in Biscay, Spain.

Subjects and method: We used the capture-recapture method: primary cases were prospectively extracted from the hospital registry and a secondary independent data source was obtained from diabetes associations and a public health database. The IRs standardized by age and sex were calculated using the direct method, assuming an equal distribution in each age/sex group. The IR occurring during the various COVID-19 waves was compared with the pre-pandemic IR.

Results: A total of 378 new cases were identified. The mean age at diagnosis was 9.7 years (5.8-11.9). The completeness of ascertainment was 99.1%. The mean annual age-standardized IR was 12.92 (95%CI, 11.35-13.91). The mean IRs for the 0-4, 5-9, and 10-14 age groups were 7.67, 13.41 and 17.83 cases/100,000 children/year, respectively. The IR trend was statistically significant in the entire group and in the 5-9 year-old group with a mean annual increase of 1.9% (95%CI, 0.1-3.8) and 3.3% (95%CI, 1.002-1.065); p=0.039. The 5-year period analysis confirmed that the increase was significant only in the last 5 years (20%). When 2020-2022 (pandemic) and 2017-2019 (pre-pandemic) periods were compared this difference goes up to 44.5%; p=0.029.

Conclusions: After a long period of stability in the IR of T1DM in children younger than 15 years of age in Biscay, Spain, an increase in recent years has been reported, which is consistent with the SARS-CoV2 pandemic, with the largest increase being reported in the 5-to 9-year-old age group.