Does vitamin D administered to children with asthma treated with inhaled glucocorticoids affect short-term growth or bone turnover?

Our objective was to assess whether administration of 25-OH-vitamin D to children with asthma treated with inhaled dry-powder budesonide 400 microg daily affects short-term growth or markers of bone turnover. We utilized a randomized, double-blind, two-period crossover trial with run-in and washout periods of 2 weeks and treatment periods of 4 weeks duration. The setting was an Outpatient clinic in a secondary referral center. Subjects included 14 boys and 3 girls with a mean age of 11.7 (range, 6.1-14.4) years. Interventions included 15 microg (600 IU) 25-OH-vitamin D (cholecalciferol) in one tablet ABCDin(R) once daily in the morning. Primary outcome measures were: lower leg growth rate, serum osteocalcin, and serum markers of type I collagen turnover, i.e., the amino terminal propeptide of type I procollagen (PINP), the carboxy terminal propeptide of type I procollagen (PICP) (formation markers), and the carboxy terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP) (degradation markers). Secondary outcome measures were parameters of asthma control and serum 25-OH-vitamin D. Lower leg growth rate was 0.22 mm/week during vitamin D and 0.25 mm/week during placebo treatment (NS). Osteocalcin was 59.9 and 57.8 microg/l during vitamin D and placebo treatment, respectively, PINP 574 and 565 microg/l, PICP 381 and 382 microg/l, and ICTP 11.5 and 11.1 microg/l, respectively (NS). Serum 25-OH-vitamin D was 76.3 nmol/l and 48.2 nmol/l, respectively (P < 0.001). There were no statistically significant differences in measures of pulmonary function. In conclusion, administration of 25-OH-vitamin D does not affect short-term growth or markers of bone turnover in children with asthma treated with inhaled dry-powder budesonide 400 microg daily.