Epidemiologic data has shown an association of low serum vitamin D levels in asthmatics with increased airway obstruction and elevated corticosteroid requirement. Several recent studies have suggested that low serum vitamin D can influence the severity of asthma and/or atopy. However age specific relationships of vitamin D were not addressed.
In a manuscript in The Journal of Allergy & Clinical Immunology (JACI), Goleva et al examined the relationships between serum vitamin D levels, markers of activation of vitamin D receptor regulated pathways, corticosteroid requirements and peripheral blood mononuclear cells responsiveness to corticosteroid treatment in vitro in asthmatic patients. The goal of the study was to evaluate whether these associations differed in adults and children. This knowledge is critical to justify potential benefits from vitamin D supplementation in different age groups of asthmatics.
The researchers acquired data from 103 patients with asthma and 102 normal controls. All samples were collected in the winter/early spring season in Denver, Colorado. The authors demonstrated that serum vitamin D levels in asthmatics were not different from general population. Close to 50% of study subjects in both groups had serum vitamin D levels in the deficient range (<20ng/ml). At the same time the results of this study demonstrate higher prevalence of vitamin D insufficiency/deficiency in adults then children. Importantly, prevalence of vitamin D insufficiency/deficiency in children older then 12 years old was shown to be similar to adults. Since in this study all samples were collected during the season when skin production of vitamin D is minimal, the findings emphasize the importance of nutrition and life style factors that determine higher serum vitamin D levels in children.
The researchers reported that only pediatric asthma group in this study showed significant inverse association between serum vitamin D levels and serum IgE levels a marker of atopy. As well, only in the pediatric group serum were vitamin D levels inversely related to patient’s corticosteroid dose. Vitamin D regulated gene expression cytochrome 24A expression in peripheral blood showed correlation with patients’ cells ability to respond to suppressive effects of corticosteroids in cell culture. These associations were not significant in the adult asthma group.
The authors’ findings suggest that vitamin D supplementation in children with asthma may enhance corticosteroid responses, control atopy and could thereby improve asthma control.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.
American Academy of Allergy, Asthma & Immunology.