A randomized double-blind placebo-controlled trial of vitamin D supplementation in juvenile-onset systemic lupus erythematosus: positive effect on trabecular microarchitecture using HR-pQCT

Summary In this randomized double-blind placebo-controlled 24-week trial, cholecalciferol supplementation at 50,000 IU/week effectively improved bone microarchitecture parameters in juvenile-onset systemic lupus erythematosus (JoSLE) patients, as assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) at tibia site. An increase in the trabecular number and a decrease in the trabecular separation were observed, suggesting that vitamin D supplementation may be recommended for JoSLE patients with its deficiency. Introduction Vitamin D has an important effect on bone but there are no trials that directly address the boosting of serum levels of 25-hydroxyvitamin D (25OHD) in bone microarchitecture in JoSLE patients. The aim of this study was to evaluate the effect of vitamin D supplementation on bone microarchitecture parameters using HR-pQCT in JoSLE patients. Methods This study was a randomized double-blind placebo-controlled 24-week trial. Forty female JoSLE patients were randomized (1:1) to receive oral cholecalciferol at 50,000 IU/week (JoSLE-VitD) or placebo (JoSLE-PL). The medications remained stable throughout the study. Serum levels of 25OHD were measured using a radioimmunoassay. The bone microarchitecture and volumetric bone density were analyzed using HR-pQCT at tibia site. Results At baseline, the groups were similar with respect to their age, body mass index, organ involvement, glucocorticoid dose, immunosuppressant use, serum 25OHD levels, and HR-pQCT parameters. After 24 weeks, higher 25OHD levels were observed in the JoSLE-VitD group compared to the JoSLE-PL group [31.3 (8.6) vs. 16.5 (5.8) ng/mL, p < 0.001]. An increase in the trabecular number [∆Tb. N 0.16 (0.24) vs. 0.03 (0.19) 1/mm, p = 0.024] and a decrease in the trabecular separation [∆ThSp −0.045 (0.067) vs. 0.001 (0.009) mm, p = 0.017] were found in the JoSLE-VitD group compared to the JoSLE-PL group at tibia site. No differences were observed in other structural parameters [trabecular (Tb.Th) or cortical thickness (Ct.Th)], volumetric bone mineral densities, cortical porosity, and biomechanical parameters ( p > 0.05). Conclusion This study suggests that cholecalciferol supplementation for 24 weeks effectively improved the bone microarchitecture parameters, mainly the trabecular number, in JoSLE patients. Trial Registration NCT01892748