Background: The association of low serum 25 hydroxy cholecalciferol (25OHD) levels with high glucose level and diminished insulin sensitivity suggests that vitamin D (VD) may modulate insulin metabolism. The aim of the study was to screen for vitamin D deficiency (VDD) in pediatric patients with type 1 diabetes (T1D) and study the effect of VD supplementation on their glycemic control and insulin requirements.
Methods: A prospective cohort study including 50 patients with T1D. VD level was assessed initially and after 3 months of VD supplementation (in those with VDD). HbA1c and insulin requirements were studied at 0, 3 and 6 months of supplementation.
Results: Fifty patients with T1D were included with mean diabetes duration of 4.11±2.34 years. VD level ranged from 0.2 to 33 ng/mL. VD status correlated significantly with daily insulin dose (p=0.030, r=0.306) and HbA1c (p<0.001, r=0.243). Thirty-five patients (70%) had VDD and were allocated for VD supplementation for 3 months. The mean HbA1c improved significantly after supplementation (p=0.003), followed by a significant deterioration at 6 months with no change in their insulin requirements at 3 or 6 months.
Conclusions: VD was highly prevalent in Egyptian T1D patients. VD supplementation improved glycemic control at 3 months after therapy with no reduction in insulin requirements.
Keywords: 25OHD; glycemic control; type 1 diabetes; vitamin D supplementation.