Vitamin D levels and skeletal quality of life in adult Langerhans cell histiocytosis

This study aims to prospectively evaluate the association between vitamin D optimization and quality of life (QoL) and bone metabolism in adult patients with Langerhans cell histiocytosis (LCH).

In this prospective, uncontrolled, observational study, 45 adult LCH patients received individualized cholecalciferol supplementation for 3 months to achieve serum 25-hydroxyvitamin D (25(OH)D) levels ≥30 ng/mL. Skeletal-related and general QoL were assessed using the QUALEFFO-41 and SF-36 questionnaires, respectively. Biochemical markers of calcium metabolism and bone turnover were measured at baseline and follow-up. Correlation and exploratory linear regression analyses evaluated associations between changes in parameters.

Levels of 25(OH)D increased significantly (22.8 ± 10.3 to 34.3 ± 8.2 ng/mL, P < 0.0005), followed by a reduction in parathyroid hormone (PTH) (55.7 ± 21.1 to 49.0 ± 15.8 pg/mL, P = 0.024). Improvements were observed in QUALEFFO-41 subdomains (household activities and mental condition) and SF-36 domains (bodily pain and emotional role limitations). C-terminal telopeptide (CTX) levels decreased (P = 0.006), consistent with reduced bone resorption. Changes in 25(OH)D were inversely correlated with changes in PTH (r = -0.35, P = 0.024), and changes in PTH were correlated with changes in CTX (r = -0.41, P = 0.007). No correlation was found between changes in 25(OH)D and CTX.

In this uncontrolled cohort, vitamin D optimization was associated with improvements in selected QoL domains and favourable changes in calcium metabolism and bone resorption markers, supporting routine assessment and correction of vitamin D deficiency in this population.