There was no significant effect for asthma symptom scores and lung function .
Conclusions and Relevance R and omized controlled trials provide some low- quality evidence to support vitamin D supplementation for the reduction of asthma exacerbations .
Importance There is growing evidence that vitamin D plays a role in the pathogenesis of asthma but it is unclear whether supplementation during childhood may improve asthma outcomes .
Objectives The objective of this systematic review and meta- analysis was to evaluate the efficacy and safety of vitamin D supplementation as a treatment or adjunct treatment for asthma .
Lack of a relation between serum 25-hydroxyvitamin D concentrations and asthma in adolescents.
BACKGROUND Decreased 25-hydroxyvitamin D [ 25(OH)D ] concentrations have been associated with an increased prevalence and severity of asthma and a lower response to inhaled corticosteroids . OBJECTIVE The objective was to determine the association between serum 25(OH)D concentrations and asthma prevalence , severity , and response to asthma treatment . DESIGN Secondary analyses were conducted in 2 sample s of adolescents 12 - 20 y of age : 1 ) NHANES 2001 - 2006 ( n = 6487 ) , a cross-sectional nationally representative sample of the US population , and 2 ) a cohort of inner-city adolescents with asthma managed prospect ively for 46 wk with guidelines -based therapy in the Asthma Control Evaluation ( ACE ; n = 226 ) trial .  RESULTS Mean ( ±SD ) serum 25(OH)D concentrations in the NHANES and ACE sample s were lower in African Americans than in non-African Americans ( NHANES : 14.9 ± 6.5 compared with 23.0 ± 8.4 ng/mL , P < 0.0001 ; ACE : 11.2 ± 6.9 compared with 15.8 ± 7.1 ng/mL , P < 0.0001 ) . In the NHANES sample , mean concentrations did not differ between participants without and with asthma ( African Americans : 14.9 ± 6.4 compared with 15.0 ± 6.6 ng/mL , respectively , P = 0.87 ; non-African Americans : 23.0 ± 8.5 compared with 23.6 ± 8.2 ng/mL , respectively , P = 0.16 ) . In the ACE models that used either a predefined cutoff ( < 20 ng/mL ) or linear regression , 25(OH)D concentrations showed either no relation or minor contradictory correlations with indicators of asthma severity , treatment requirements , spirometry , or atopy/inflammation . CONCLUSION In 2 sample s of adolescents , overall serum 25(OH)D concentrations were low and were not consistently associated with the presence of asthma , multiple asthma characteristics , asthma morbidity , or response to treatment . The ACE trial was registered at clinical trials.gov as NCT0011441
There was no significant effect for asthma symptom scores and lung function .
Conclusions and Relevance R and omized controlled trials provide some low- quality evidence to support vitamin D supplementation for the reduction of asthma exacerbations .
Importance There is growing evidence that vitamin D plays a role in the pathogenesis of asthma but it is unclear whether supplementation during childhood may improve asthma outcomes .
Objectives The objective of this systematic review and meta- analysis was to evaluate the efficacy and safety of vitamin D supplementation as a treatment or adjunct treatment for asthma .