Endocrine Abstracts

JOINT2563

The aim of the study was to assess the relationship between vitamin D3 concentration and the titer of anti-SARS-CoV-2 IgG antibodies in type 1 diabetes children (T1D).

Methods: Between June 1, 2021 and June 1, 2024, a cross-sectional study was conducted among T1D children. The control group consisted of children without carbohydrate metabolism disorders and autoimmune diseases. The titer of anti-SARS-CoV-2 IgG antibodies, the concentration of 25(OH) vitamin D3 and HbA1c were determined. Vitamin D3 deficiency was diagnosed if <30 ng/ml, and anti-SARS-CoV-2 IgG seropositivity if ≥7.1 BAU/ml.

Results: The study group included 232 children (122 boys), 196 people with diabetes, aged 12.5 ± 4.0 years, in whom a total of 289 tests were performed (in 51 T1D children test was performed ≥twice). The median 25(OH)D3 concentration was 26.6 [IQR=15.6] ng/ml and did not differ depending on gender, diagnosis of T1D or co-occurrence of other diseases (P>0.05). Vitamin D3 deficiency was diagnosed in 178 children (61.6%). The concentration of 25(OH)D3 was lower in the group of children with new T1D (Me=21.8 [IQR=9.5] ng/ml), compared to long-lasting T1D (Me=27.75 [IQR=17, 2] ng/ml) and in the controls (Me=28.3 [IQR=18.6] ng/ml), P = 0.0093. Anti-SARS-CoV-2 IgG Ab seropositivity reached 95.5%, median titer was 307.2 [IQR = 624.8] BAU/ml, did not differ depending on gender, vitamin D3 supplementation and vaccination (P>0.05), as well on the co-occurrence of other diseases (P>0.05). In T1D, the anti-SARS-CoV-2 IgG Ab titer was higher than in the controls (Me=328.7 [IQR=677.4] BAU/ml vs. Me=169.4 [IQR=402.6] BAU/ml), P = 0.0130. The Ab titer in new T1D (Me=122.0 [IQR=559.4] BAU/ml) was lower compared to the long-lasting T1D (Me=359.7 [IQR=678.6] BAU/ml) and controls, P<0.0001. There was a correlation between anti-SARS-CoV-2 IgG Ab and age (R=0.3359, P<0.0001) and HbA1c and 25(OH)D3 (R=-0.3267, P<0, 0001). Children seronegative for SARS-CoV-2 (n= 13, 5.6%) were younger (7.4±5.4 years vs. 12.6±3.9 years), P = 0.0241, 25 (OH)D3 (Me=25.9 [IQR=114.7] ng/ml vs. Me=26.6 [IQR=16.2] ng/ml) and HbA1c (Me=8.0 [IQR=6).6] % vs. Me=7.3 [IQR=2.5] %) were comparable to AntiSARS-Cov2(+).

Conclusions: In children with type 1 diabetes, the titer of anti-SARS-CoV-2 IgG antibodies did not depend on the concentration of vitamin D3, however, in the group of children with the lowest 25(OH)D3 concentration, the titer of IgG anti-SARS-CoV-2 antibodies was also lowest. Lower titers of these antibodies in younger children indicate a weaker immune response in this group. Vitamin D3 deficiency occurring in the majority of respondents indicates the need for its systematic supplementation.