Skip to content
DraconiticResearch
Search Sources API
201,818 studies31 sourcesUpdated 29 min ago
Peer-reviewedCC BY 4.0PLOS Medicine

Trends in the incidence of childhood type 1 diabetes after the COVID-19 lockdown in Finland: An observational study

  • Susanna Tall1
  • Maaret Turtinen2
  • Anna Parviainen3
  • Jenni Pettersson4
  • Anna But5
  • Taina Härkönen6
  • Jussi Hepojoki7
  • Tarja Sironen8
  • Rommel Iheozor-Ejiofor9
  • Hasan Uğurlu10
  • Kalle Saksela11
  • Jorma Ilonen12
4 more authors
  • Suvi M. Virtanen13
  • Olli Vapalahti
  • Mikael Knip
  • on behalf of the Finnish Pediatric Diabetes Register
13 affiliations
  1. 1Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
  2. 2Department of Public Health, Finnish Institute for Health and Welfare, Helsinki, Finland
  3. 3Pediatric Research Center, New Children’s Hospital, Helsinki University Hospital, Helsinki, Finland
  4. 4Department of Virology, Medicum, University of Helsinki, Helsinki, Finland
  5. 5Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
  6. 6Biostatistics Consulting, Department of Public Health, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
  7. 7Erzurum Technical University, Erzurum, Turkey
  8. 8Virology and Immunology, Helsinki University Hospital Diagnostic Center, Helsinki, Finland
  9. 9Immunogenetics Laboratory, Institute of Biomedicine, University of Turku, Turku, Finland
  10. 10Tampere Center for Child, Adolescent and Maternal Health Research, Tampere University and Tampere University Hospital, Tampere, Finland
  11. 11Tampere University Hospital, Wellbeing Services County of Pirkanmaa, Tampere, Finland
  12. 12Faculty of Social Sciences, Unit of Health Sciences, Tampere University, Tampere, Finland
  13. 13Turku, Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
Read full textPDFDOICite

Abstract

Background: While COVID-19 lockdowns have been systematically associated with increased incidence rate of type 1 diabetes, less is known about the disease rates after lockdowns. We compared the incidence of type 1 diabetes after the COVID-19 pandemic-related closure of society (i) to the time when lockdown was implemented and to (ii) the time before the pandemic in Finland. Methods and findings: The incidence of type 1 diabetes after the lockdown (09/2021–12/2022) was compared to the incidence during the lockdown (03/2020–08/2021) and before the lockdown (three 18-month terms 2014–2019) in Finnish children under the age of 15 years. Previous exposure to SARS-CoV-2 was identified by combining information on COVID-19 vaccination with data on SARS-CoV-2 antibodies analyzed in blood samples. The temporal cohort included 3,467 pediatric type 1 diabetes cases, distributed across post-lockdown (n = 586), lockdown (n = 785), and pre-pandemic (n = 2,096) periods. The incidence of type 1 diabetes after the lockdown was significantly lower than the incidence during the lockdown [incidence rate ratio (IRR = 0.85; 95% Cl [0.77,0.95]; p = 0.004)]. The rate of type 1 diabetes after the lockdown did not significantly differ from the time before lockdown (IRR = 1.00; 95% Cl [0.91,1.09]; p = 0.932). The frequency of children testing positive for infection-associated SARS-CoV-2 antibodies increased from 0.9% during the lockdown to more than 40% after the lockdown. Study limitations include a relatively short follow-up period after the lockdown and the lack of explicit modeling of the underlying long-term secular trend in type 1 diabetes incidence. Conclusions: The lockdown represents a peak in childhood type 1 diabetes incidence in Finland compared to both the pre-pandemic and post-lockdown periods. However, the reversion toward historical levels after the lockdown does not necessarily establish a return to the expected historical trajectory, nor can it fully distinguish a transient change from temporal compensation superimposed on the background secular trend. The contrasting patterns between type 1 diabetes incidence and SARS-CoV-2 antibody prevalence during and after the lockdown suggest an indirect rather than a direct role of the virus in triggering the observed changes in incidence. Why was this study done?: What did the researchers do and find?: What do these findings mean?: In this observational study, Susanna Tall and colleagues found that childhood type 1 diabetes incidence declined in Finland after COVID-19 lockdown restrictions ended, returning to levels comparable with those observed before the pandemic. Their findings suggest that the elevated incidence seen during the lockdown period represented a temporary peak.

Related

  1. Tooth wear and socioeconomic status in childhood and adulthood: Findings from a systematic review and meta-analysis of observational studies
    Sheema Entezami, Karen Glazer Peres, Huihua Li +3
    Journal of DentistryPeer-reviewedLicence not stated24 citedGeneral biologyEpidemiology & public healthHAL
  2. The Enigma of Finnish and Sardinian Type 1 Diabetes Incidence: Where Population History Meets Genetics
    GenesPeer-reviewedCC BYFull textGenetics & genomicsEurope PMC
  3. Rotavirus vaccination and incidence of type 1 diabetes: a population-based natural experiment
    Maria Östman, Ketil Størdal, German Tapia +1
    DiabetologiaPeer-reviewedCC BY 4.0Full textGenetics & genomicsPMC
  4. Depressive symptoms are associated with the incidence of frailty in older adults with cardiometabolic diseases: Interaction between depression and diabetes
    Fumino Kobayashi, Yoshiaki Tamura, Yuji Murao +10
    PLOS OnePeer-reviewedCC BY 4.0Full textNeuroscienceEndocrinology & metabolismPLOS
  5. Higher intake of dietary dicarbonyl compounds is associated with lower incidence of type 2 diabetes: European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study
    Kim Maasen, Ana-Lucia Mayen, Claudia Hana +33
    European Journal of NutritionPeer-reviewedCC BYFull text2 citedGeneral biochemistryGeneral biologyHAL

Cite

BibTeXRIS
BibTeX
@article{tall2026trends,
  title = {{Trends in the incidence of childhood type 1 diabetes after the COVID-19 lockdown in Finland: An observational study}},
  author = {Susanna Tall and Maaret Turtinen and Anna Parviainen and Jenni Pettersson and Anna But and Taina Härkönen and Jussi Hepojoki and Tarja Sironen and Rommel Iheozor-Ejiofor and Hasan Uğurlu and Kalle Saksela and Jorma Ilonen and Suvi M. Virtanen and Olli Vapalahti and Mikael Knip and on behalf of the Finnish Pediatric Diabetes Register},
  journal = {PLOS Medicine},
  year = {2026},
  month = nov,
  doi = {10.1371/journal.pmed.1005288},
  url = {https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005288},
  note = {CC BY 4.0},
}
RIS
TY  - JOUR
TI  - Trends in the incidence of childhood type 1 diabetes after the COVID-19 lockdown in Finland: An observational study
AU  - Susanna Tall
AU  - Maaret Turtinen
AU  - Anna Parviainen
AU  - Jenni Pettersson
AU  - Anna But
AU  - Taina Härkönen
AU  - Jussi Hepojoki
AU  - Tarja Sironen
AU  - Rommel Iheozor-Ejiofor
AU  - Hasan Uğurlu
AU  - Kalle Saksela
AU  - Jorma Ilonen
AU  - Suvi M. Virtanen
AU  - Olli Vapalahti
AU  - Mikael Knip
AU  - on behalf of the Finnish Pediatric Diabetes Register
PY  - 2026
DA  - 2026/11/02
JO  - PLOS Medicine
DO  - 10.1371/journal.pmed.1005288
UR  - https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005288
AB  - Background: While COVID-19 lockdowns have been systematically associated with increased incidence rate of type 1 diabetes, less is known about the disease rates after lockdowns. We compared the incidence of type 1 diabetes after the COVID-19 pandemic-related closure of society (i) to the time when lockdown was implemented and to (ii) the time before the pandemic in Finland. Methods and findings: The incidence of type 1 diabetes after the lockdown (09/2021–12/2022) was compared to the incidence during the lockdown (03/2020–08/2021) and before the lockdown (three 18-month terms 2014–2019) in Finnish children under the age of 15 years. Previous exposure to SARS-CoV-2 was identified by combining information on COVID-19 vaccination with data on SARS-CoV-2 antibodies analyzed in blood samples. The temporal cohort included 3,467 pediatric type 1 diabetes cases, distributed across post-lockdown (n = 586), lockdown (n = 785), and pre-pandemic (n = 2,096) periods. The incidence of type 1 diabetes after the lockdown was significantly lower than the incidence during the lockdown [incidence rate ratio (IRR = 0.85; 95% Cl [0.77,0.95]; p = 0.004)]. The rate of type 1 diabetes after the lockdown did not significantly differ from the time before lockdown (IRR = 1.00; 95% Cl [0.91,1.09]; p = 0.932). The frequency of children testing positive for infection-associated SARS-CoV-2 antibodies increased from 0.9% during the lockdown to more than 40% after the lockdown. Study limitations include a relatively short follow-up period after the lockdown and the lack of explicit modeling of the underlying long-term secular trend in type 1 diabetes incidence. Conclusions: The lockdown represents a peak in childhood type 1 diabetes incidence in Finland compared to both the pre-pandemic and post-lockdown periods. However, the reversion toward historical levels after the lockdown does not necessarily establish a return to the expected historical trajectory, nor can it fully distinguish a transient change from temporal compensation superimposed on the background secular trend. The contrasting patterns between type 1 diabetes incidence and SARS-CoV-2 antibody prevalence during and after the lockdown suggest an indirect rather than a direct role of the virus in triggering the observed changes in incidence. Why was this study done?: What did the researchers do and find?: What do these findings mean?: In this observational study, Susanna Tall and colleagues found that childhood type 1 diabetes incidence declined in Finland after COVID-19 lockdown restrictions ended, returning to levels comparable with those observed before the pandemic. Their findings suggest that the elevated incidence seen during the lockdown period represented a temporary peak.
SN  - 1549-1676
ER  -