Effect of Cholecalciferol Supplementation on Bone Turnover Markers in Children and Adolescents With Type 1 Diabetes Mellitus

Background: Cholecalciferol is known to play an important role in bone mineral metabolism. Its deficiency may affect growth and status of bone markers in children. Aim of the study: to evaluate the correlation between serum 25(OH)D and bone markers and impact of vitamin D supplementation on serum bone formation [procollagen type 1 amino-terminal propeptide (P1NP)] and bone resorption [β-cross laps (CTx)] markers among children and adolescents with type 1 diabetes mellitus (DM). Materials and Methods: Total 58 children and adolescents with type 1 DM, who were given 2000 UI of cholecalciferol supplementation, were included in the study. These 58 children with available anthropometry, serum biochemistry, 25-hydroxyvitamin D ([25(OH)D]), and parathormone (PTH) were evaluated for bone formation (procollagen type 1 amino-terminal propeptide [P1NP]) and resorption (β-cross laps [CTx]) markers. Results: The mean age and body mass index of these children were 11.6 ± 2.3 years (boys: 11.7 ± 2.4; girls: 12.2 ± 1.4 years; p = 0.04) and 18.2 ± 3.9 kg/m(2) (boys: 18.1 ± 3.8; girls: 17.8 ± 3.4 kg/m(2); p = 0.206), respectively. Baseline serum P1NP levels were positively correlated with serum phosphates (r = 0.281, p < 0.001), PTH (r = 0.291, p < 0.001), and CTx (r = 0.425, p < 0.001) but not with age (r = -0.016, p = 0.404), BMI (r = -0.080, p = 0.032), serum calcium (r = -0.038, p = 0.107), and baseline 25(OH)D (r = -0.069, p = 0.035). Postsupplementation serum P1NP and CTx levels maintained similar correlations. There was a significant decline in serum P1NP (from 681 ± 223 ng/ml to 630 ± 279 ng/ml, p < 0.01) and CTx (from 1.63 ± 0.51 ng/ml to 1.37 ± 0.53 ng/ml, p < 0.01) following supplementation. Though decline in serum P1NP and CTx levels was observed in both boys and girls, among all supplementation patients, the effect was more marked in serum CTx than P1NP levels. Conclusions: Vitamin D supplementation in children resulted in decrease in both bone formation (P1NP) and resorption (CTx). The impact, however, was more marked on bone resorption than bone formation.