The COVID-19 Pandemic Affects Seasonality, With Increasing Cases of New-Onset Type 1 Diabetes in Children, From the Worldwide SWEET Registry.

OBJECTIVE: To analyze whether the coronavirus disease 2019 (COVID-19) pandemic increased the number of cases or impacted seasonality of new-onset type 1 diabetes (T1D) in large pediatric diabetes centers globally. RESEARCH DESIGN AND METHODS: We analyzed data on 17,280 cases of T1D diagnosed during 2018–2021 from 92 worldwide centers participating in the SWEET registry using hierarchic linear regression models. RESULTS: The average number of new-onset T1D cases per center adjusted for the total number of patients treated at the center per year and stratified by age-groups increased from 11.2 (95% CI 10.1–12.2) in 2018 to 21.7 (20.6–22.8) in 2021 for the youngest age-group, <6 years; from 13.1 (12.2–14.0) in 2018 to 26.7 (25.7–27.7) in 2021 for children ages 6 to <12 years; and from 12.2 (11.5–12.9) to 24.7 (24.0–25.5) for adolescents ages 12–18 years (all P < 0.001). These increases remained within the expected increase with the 95% CI of the regression line. However, in Europe and North America following the lockdown early in 2020, the typical seasonality of more cases during winter season was delayed, with a peak during the summer and autumn months. While the seasonal pattern in Europe returned to prepandemic times in 2021, this was not the case in North America. Compared with 2018–2019 (HbA_1c 7.7%), higher average HbA_1c levels (2020, 8.1%; 2021, 8.6%; P < 0.001) were present within the first year of T1D during the pandemic. CONCLUSIONS: The slope of the rise in pediatric new-onset T1D in SWEET centers remained unchanged during the COVID-19 pandemic, but a change in the seasonality at onset became apparent. [ABSTRACT FROM AUTHOR]