Table 1.
Summary of clinical studies examining vitamin D status and asthma
| Investigator | Population studied | Vitamin D status assessed by | Effects of vitamin D in population studied |
| Pregnancy | |||
| Erkkola (23) | Prospective cohort of pregnant mothers and their children in Finland | Maternal diet (FFQ) | Maternal vitamin D intake resulted in a lower risk of asthma in children at 5 y old |
| Camargo (20) | Prospective cohort of pregnant mothers and their children in USA | Maternal diet (FFQ) | Maternal intake of vitamin D reduced the risk of wheezing in children at 3 y old |
| Miyake (21) | Prospective cohort of Japanese pregnant women and their children | Maternal diet (FFQ) | Maternal intake of vitamin D at >25% percentile lowered the risk of wheezing in children by 16–24 mo old |
| Devereux (22) | Case-control study of pregnant women and their children | Maternal diet (FFQ) | Highest quintile for maternal intake of vitamin D compared to lowest quintile lowered risk of wheezing in children at 5 y old |
| Gale (51) | Prospective cohort of pregnant women and their children in the UK | Maternal 25(OH)D | Maternal 25(OH)D >30 ng/ml increased the risk of asthma in children at 9 y old compared to <12 ng/ml |
| Childhood | |||
| Hypponen (50) | Prospective cohort of children starting at age 1 y and followed for 30 y | Not assessed | Vitamin D supplementation was associated with a nonsignificant increase in risk of asthma at 31 y old |
| Brehm (10) | Cross-sectional study of Costa Rican children | 25(OH)D | Vitamin D insufficiency (<30 μg/L) in 6- to 14-y-old children was associated with an increase in rate of any hospitalization, any use of anti inflammatory medications, and increased airway responsiveness |
| Chinellato (11) | Cross-sectional study of Italian children 5–11 y old | 25(OH)D | Decreased 25(OH)D was associated with a reduction in asthma control |
| Freishtat (41) | Cross-sectional case control study of children 6–20 y old with and without asthma in USA | 25(OH)D | Vitamin D deficiency more common in asthmatics |
| Searing (45) | Cross-sectional study of children with asthma | 25(OH)D | Vitamin D status [25(OH)D] inversely correlated with increased corticosteroid usage and positively correlated with FEV1 and FEV1/FVC |
| Brehm (40) | Children with mild to moderate asthma randomized to 1 of 4 controller medications | 25(OH)D | Vitamin D insufficiency (<30 μg/L) was associated with an increased rate of severe asthma exacerbation |
| Hughes (44) | Retrospective cohort of Australian adults 18–61 y old | 25(OH)D | Vitamin D status [25(OH)D] was not associated with history of childhood asthma |
| Camargo (49) | Prospective cohort of newborns | Cord blood 25(OH)D | 25(OH)D cord blood concentrations were inversely associated with risk of respiratory infections and wheezing, but not with asthma by 5 y old |
| Chinellato (46) | Cross-sectional study of Italian children with intermittent asthma | 25(OH)D | 25(OH)D was inversely correlated with impairment in lung function and increased bronchoconstriction to exercise |
| Adult | |||
| Sutherland (24) | Cross-sectional study of adults with asthma | 25(OH)D | Low 25(OH)D concentrations were associated with impaired lung function, increased airway hyper-responsiveness |
| Li (42) | Cross-sectional study of Chinese adults 18 y or older with a new diagnosis of asthma | 25(OH)D | Vitamin D deficiency was present in the Chinese population and had a positive association with lung function |
| Devereux (43) | Case-control study of Scottish adults 18–50 y old with mild to moderate asthma | 25(OH)D | Vitamin D status was not associated with asthma and Scottish adults |