title: Asthma, allergy and respiratory infections: the vitamin D hypothesis.
abstract: The recent discovery that every tissue in the human body has vitamin D receptors and that vitamin D has pleiotropic effects has prompted an increased interest in this hormone. Vitamin D deficiency is widespread and on the increase. There is no consensus on the serum vitamin D levels to consider appropriate for global health, the cutoffs for its deficiency, or the doses to use for its supplementation. Vitamin D seems to correlate closely with host reactions against various respiratory infections. Epidemiological studies have shown that low serum 25-hydroxyvitamin D levels are associated with a higher risk of upper and lower respiratory infections in children and a shortage of vitamin D may contribute to asthmatic patients' symptoms and morbidity rates. There are studies highlighting associations between childhood asthma, fetal lung and/or immune development, and maternal vitamin D intake. An insufficiency of this vitamin also seems to be implicated in the onset of childhood atopy and food allergies. The hypothesis is that vitamin D could have a central role in these pathological situations and that it may represent a novel preventive and/or therapeutic strategy. This article reviews and discusses published data on the relationship between vitamin D and asthma and allergy, emphasizing the need for controlled, prospective studies on vitamin D supplementation to clarify whether it has a role in the prevention of and treatment for asthma and allergic conditions.
authors.affiliation: Allergy Unit and Respiratory Medicine, Department of Pediatrics, University of Padova, Via Giustiniani 3, Padua, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Bozzetto
authors.forename: S
authors.initials: S
authors.lastname: Carraro
authors.forename: G
authors.initials: G
authors.lastname: Giordano
authors.forename: A
authors.initials: A
authors.lastname: Boner
authors.forename: E
authors.initials: E
authors.lastname: Baraldi
mesh_terms: D001249:Asthma / Q000097:blood* / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000097:blood* / Q000276:immunology; D012141:Respiratory Tract Infections / Q000097:blood* / Q000276:immunology; D014807:Vitamin D / Q000097:blood / Q000276:immunology*; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D