Incidence Trends of Type 1 Diabetes in Estonian Children (1983–2022) and the Impact of the COVID‐19 Pandemic

Background: The annual incidence rate (IR) of childhood‐onset type 1 diabetes mellitus (T1DM) among Estonian children under 15 years of age was 12.6 cases per 100,000 between 1983 and 2006, with the highest IR occurring in the 10–14‐year‐old age group. Notably, the 0–4‐year‐old age group saw the most significant annual increase, at 9.3%. Objective: This study aims to determine the incidence and trends of T1DM among Estonian children from 1983 to 2022, focusing on the period from 2007 to 2022. Additionally, the study evaluates the impact of the COVID‐19 pandemic on the incidence of T1DM in this population. Subjects and Methods: This retrospective cohort study gathered data from 2007 to 2022 using population‐based registries from Estonia’s paediatric medical centers. Preceding data were sourced from previous publications. The subjects were divided into three age groups, and the study period was segmented into five time periods, each spanning 8 years. Results: From 2007 to 2022, 1104 new T1DM cases were diagnosed in children under 15 years in Estonia, with a crude IR of 32.9 per 100,000 persons per year (95% confidence interval [CI] 30.9–34.8). The highest incidence was in the 10–14‐year age group (40.5 per 100,000 per year) (95% CI 36.7–44.3). On average, the incidence grew by 1.6% during this time period for all age groups combined. The most significant growth was in the 5–9‐year‐old group, with an annual increase of 2.9% (relative risk [RR] 1.23, 95% CI 1.0–1.5). The highest IR ever recorded in Estonia was in 2021, during the highest fatality year of COVID‐19, at 45.8 per 100,000 (95% CI 26.9–54.8). Conclusions: The incidence of childhood‐onset T1DM in Estonia continues to rise, with a notable spike in 2021 during the peak of the COVID‐19 pandemic.