BMJ Paediatrics Open (May 2024)

Vitamin D insufficiency in infants with increased risk of developing type 1 diabetes: a secondary analysis of the POInT Study

  • Anette-Gabriele Ziegler,
  • Kristina Casteels,
  • Olga Kordonouri,
  • Helena Elding Larsson,
  • Markus Lundgren,
  • Agnieszka Szypowska,
  • Ezio Bonifacio,
  • Christiane Winkler,
  • Rachel Besser,
  • Andreas Weiss,
  • Mariusz Ołtarzewski,
  • John A. Todd,
  • An Jacobs,
  • Angela Hommel,
  • Maarten Warnants,
  • Veronika Vollmuth,
  • Thekla von dem Berge,
  • Marie-Luise Zielmann

DOI
https://doi.org/10.1136/bmjpo-2023-002212
Journal volume & issue
Vol. 8, no. 1

Abstract

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Background Vitamin D insufficiency (VDI) may be a factor in the development of type 1 diabetes (T1D). The aim of this study is to investigate the presence and persistence of VDI in a large cohort of infants with increased risk of developing T1D, in light of the differences in local supplementation guidelines.Methods In the POInT Study, a multicentre primary prevention study between February 2018 and March 2021 in Germany, Poland, Belgium, England and Sweden, including infants aged 4–7 months at high genetic risk of developing β-cell autoantibodies, vitamin D levels were analysed at each study visit from inclusion (4–7 months) until 3 years, with an interval of 2 months (first three visits) or 4–6 months (visits 4–8). The protocol actively promotes vitamin D sufficiency to optimise immune tolerance. VDI was defined as a concentration below 30 ng/mL and was treated according to local guidelines of participating centres. Recovery from VDI was defined as a concentration above or equal to 30 ng/mL on the subsequent visit after VDI.Results 1050 infants were included, of which 5937 vitamin D levels were available for analyses. VDI was observed in 1464 (24.7%) visits and 507 (46.1%) of these were not resolved at the next visit. The risk of having VDI was independently associated with season (higher in winter), weight (higher with increased weight), age (higher with increased age) and country (higher in England). The risk of not recovering from VDI was independently associated with the season of the previously determined VDI, which was higher if VDI was identified in winter.Conclusions VDI is frequent in infants with increased risk of developing T1D. Treatment guidelines for VDI do not seem effective. Increasing supplementation dosages in this patient population seems warranted, especially during winter, and increasing dosages more aggressively after VDI should be considered.