Background: The aim of this study was to evaluate the effect of short-term vitamin D supplementation on the decline of residual beta cell function (RBCF) in children with type 1 diabetes (T1D).
Methods: The study involved an intervention group (cholecalciferol 2000 IU/day and calcium 25 mg/kg/day for 6 months) comprising 15 children aged 6-12 years and within 1-2 years of diagnosis of T1D. Fifteen age-matched T1D patients were followed up as controls. Stimulated C-peptide levels were estimated at baseline and 6 months.
Results: The mean decrease in stimulated C-peptide levels in the intervention group was lower (-0.048±0.15 ng/mL) as compared with the controls (-0.107±0.23 ng/mL) but did not reach statistical significance (p=0.472). The percent decrease in stimulated C-peptide from baseline to endpoint (8.3% vs. 20.3%, p=0.357) and the monthly decrease (0.008 ng/mL vs. 0.017 ng/mL, p=0.22) were non-significantly lower in the intervention group compared with the control group. Three (20%) patients progressed to undetectable stimulated C-peptide (≤0.01 ng/mL) over the study period in the control group as compared with one (6%) in the intervention group (p-value 0.260).
Conclusions: There was a trend towards lesser decline of RBCF with short term cholecalciferol supplementation in children with T1D. Further larger studies are urgently needed to explore the beneficial effects of the relatively inexpensive vitamin D supplementation on RBCF.