The COVID-19 Pandemic Affects Seasonality, With Increasing Cases of New-Onset Type 1 Diabetes in Children, From the Worldwide SWEET Registry
Authors: Reschke Felix , Lanzinger Stefanie , Herczeg Vivien , Prahalad Priya , Schiaffini Riccardo , Mul Dick , Clapin Helen , Zabeen Bedowra , Pelicand Julie , Phillip Moshe , Limbert Catarina , Danne Thomas ,   on behalf of the SWEET Study Group, Alonso G. Todd , Rhodes Erinn T. , Davis Elizabeth , Veeze Henk J. , Maahs David , Cardona-Hernandez Roque , Sumnik Zdenek , Corathers Sarah , Bratina Natasa , Danne Thomas , Gevers Evelien , Imane Zineb , Piccini Barbara , Forsander Gun , Pacaud Daniele , Maffeis Claudio , Campbell Fiona , Bonfanti Riccardo , de Sanctis Luisa , Krone Ruth Elisabeth , Toth-Heyn Peter , Witsch Michael , Arsanoglu Ilknur , Jefferies Craig , Landry Alanna , Beltrand Jacques , Amed Shazhan , Rami-Merhar Birgit , Barat Pascal , Szypowska Agnieszka , Zabeen Bedowra , Casteels Kristina , Savova Radka , Cherubini Valentino , de Bock Martin , Todorovic Sladjana , Limbert Catarina , Moravej Hossein , Pozgaj Sepac Marija , Mazur Artur , Gerasimidou-Vazeou Andriani , Iotova Violeta , O’Riordan Stephen , Chobot Agata , Herbst Antje , Ngwu Ursula , Cody Declan , Birkebæk Niels H. , Hanas Ragnar , Goksen Damla , Sarda Archana , Chobot Jarosz , Mirante Alice , Richmond Padilla Erick , Tsiroukidou Kyriaki , Saboo Banshi , Kanaka-Gantenbein Christina , Schiaffini Riccardo , Foskett Deborah , Jali Sujata , Verkauskiene Rasa , Castro-Correia Cíntia , Kumar Guness Pravesh , Pelicand Julie , Cotterill Andrew , Kumari Mohan Meena , Spehar Uroic Anita , Goss Peter , Svensson Jannet , Ramchandani G. D. , Coutant Regis , Mantilla Lucia , Sima Alexandra , Hyun Kim Jae , Galli-Tsinopoulou Assimina , Ribeiro Rogerio , O’Gorman Clodagh , Fonna Helse , Bratke Heiko , El Habashy Safinaz , Gokalani Rutul , Scharf Pinto Mauro , Chavda Vipul 
Published: September 2022

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, &lt;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 &lt;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 &lt; 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 (HbA1c 7.7%), higher average HbA1c levels (2020, 8.1%; 2021, 8.6%; P &lt; 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.