Available evidence from this systematic review suggests that high dose vitamin D may prevent  asthma exacerbation .
CONTEXT Observational studies have suggested a relationship between vitamin D status and asthma-related respiratory outcomes .
The benefit of vitamin D supplementation for pulmonary function , symptoms and exacerbations is not well established .
OBJECTIVE To systematic ally review paediatric clinical trials investigating the role of vitamin D on asthma-related respiratory outcomes .
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 r and omized , 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
Available evidence from this systematic review suggests that high dose vitamin D may prevent  asthma exacerbation .
CONTEXT Observational studies have suggested a relationship between vitamin D status and asthma-related respiratory outcomes .
The benefit of vitamin D supplementation for pulmonary function , symptoms and exacerbations is not well established .
OBJECTIVE To systematic ally review paediatric clinical trials investigating the role of vitamin D on asthma-related respiratory outcomes .