Table 2. Studies of vitamin D status in school-age children with asthma.

Author	Year	n (% male)	Age (years)	Study Design	Sample	Outcome Measures	Findings
Brehm41	2009	616 (60)	8.7	Cross-sectional	Mild-to-severe persistent asthma	Asthma exacerbations	Increased 25(OH)D associated with reduced hospitalization, reduced anti-inflammatory medication use and reduced airway hyperresponsiveness
Brehm69	2010	1024 (60)	8.9	Prospective cohort	Mild-to-moderate persistent asthma	Hospitalization or emergency department visit	Baseline 25(OH)D levels < 30 ng/mL associated with higher odds of hospitalization or emergency department over 4 y
Chinellato70	2011	75 (60)	9.6	Cross-sectional	Well-controlled and poorly controlled asthma	Spirometry, asthma control	Positive correlations noted between 25(OH)D and asthma control
Chinellato71	2011	45 (60)	10	Cross-sectional	Intermittent asthma	Lung function and airway hyperresponsiveness	Lower serum 25(OH)D associated with decreased lung function and increased airway hyperresponsiveness with exercise
Freishtat72	2010	92 (63)	11.1	Cross-sectional	African Americans with and without asthma	Physician-diagnosed asthma	Decreased 25(OH)D in asthmatics vs. controls
Majak73	2011	48 (67)	11.5	Randomized, double-blind, parallel arm clinical trial	Newly diagnosed asthma	Asthma exacerbations	Fewer exacerbations in children with vitamin D3 supplementation added to inhaled budesonide
Searing74	2010	100 (64)	7	Cross-sectional	Moderate to severe persistent asthma	Corticosteroid use and airflow limitation	Decreased 25(OH)D associated with lower lung function and higher corticosteroid requirements
Urashima75	2010	217 (57)	10.0	Randomized, double-blind clinical trial	Schoolchildren (allcomers), subgroup with physician-diagnosed asthma	Asthma exacerbations	Reduced risk of asthma exacerbations in the subgroup with asthma after vitamin D3 supplementation