ISSN 1662-4009 (online)

ESPE Yearbook of Paediatric Endocrinology (2021) 18 10.9 | DOI: 10.1530/ey.18.10.9

ESPEYB18 10. Type 1 Diabetes Mellitus (1) (14 abstracts)

10.9. Serum 25-hydroxyvitamin D concentration in childhood and risk of islet autoimmunity and type 1 diabetes: the TRIGR nested case-control ancillary study

Miettinen ME , Niinistö S , Erlund I , Cuthbertson D , Nucci AM , Honkanen J , Vaarala O , Hyöty H , Krischer JP , Knip M & Virtanen SM; TRIGR Investigators

Diabetologia. 2020;63(4):780–787. doi: 10.1007/s00125-019-05077-4.

This multicenter multinational study, in children with high genetic risk of T1D, identified an association between lower serum 25-hydroxyvitamin D (25OHD) concentrations and subsequent appearance of islet autoimmunity or T1D.

The Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) included from children in 15 countries. Case children (n=244) were defined as those positive for 2+ of 4 autoantibodies. For each case, two control children were matched for country and date of birth (n=488). Serum 25OHD levels were measured repeatedly in infancy and childhood and were related to age at the first seroconversion and calendar age. Analyses were adjusted for month of sample collection, human leucocyte antigen genotype, maternal T1D and sex.

Serum 25OHD concentrations were lower 18 months before first seroconversion in children with islet autoimmunity, than at the equivalent ages in controls (mean 57.7 vs 64.8 nmol/l, P=0.007). Of the case children, 144 developed T1D – their serum 25OHD concentrations were also lower 18 months before first seroconversion (58.0 vs 65.0 nmol/l, P=0.018) and at calendar age 12 months (70.1 vs 75.9 nmol/l, P=0.031) than in controls. These results suggest that indeed early postnatal vitamin D levels may be related to and even confer protection against the development of T1D.

Whether or not this may be of clinical relevance or could even be used as a preventive measure against the disease is still very uncertain indeed. In such observational studies, there are dozens of diseases associated with lower Vitamin D levels, and very few are confirmed by randomized controlled trials. There may be many potential confounding factors, including geography (latitude), lifestyle (sun exposure), BMI, supplement use etc.