Childhood asthma may be a consequence of vitamin D deficiency.
OBJECTIVE
Vitamin D deficiency has been rediscovered as a public-health problem worldwide. It has been postulated that vitamin D deficiency may explain a portion of the asthma epidemic. The purpose of this review is to present the evidence for a role of vitamin D in asthma.


RESULTS
Both animal models and studies in human fetal tissues show that vitamin D plays a role in fetal lung growth and maturation. Epidemiologic studies have also suggested that higher prenatal vitamin D intakes have a protective role against wheezing illnesses in young children. Vitamin D may protect against wheezing illnesses through its role in upregulating antimicrobial proteins or through its multiple immune effects. In addition, vitamin D may play a therapeutic role in steroid resistant asthmatics, and lower vitamin D levels have recently been associated with higher risks for asthma exacerbations.


CONCLUSIONS
Improving vitamin D status holds promise in primary prevention of asthma, in decreasing exacerbations of disease, and in treating steroid resistance. However, the appropriate level of circulating vitamin D for optimal immune functioning remains unclear. Because vitamin D deficiency is prevalent even in sun-replete areas, clinical trials are needed to definitively answer questions about the role of vitamin D in asthma.
Litonjua
Augusto A
AA
Channing Laboratory and Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. augusto.litonjua@channing.harvard.edu
D000818:Animals; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology* / Q000517:prevention & control; D002648:Child; D006801:Humans; D007223:Infant; D012135:Respiratory Sounds / Q000187:drug effects / Q000209:etiology / Q000276:immunology; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000502:physiology*; D014808:Vitamin D Deficiency / Q000150:complications* / Q000453:epidemiology*
D014807:Vitamin D