Asthma and Inhaled Corticosteroid use Associated with Lower Vitamin D Levels, Study Shows

   Vitamin D insufficiency is common in children with asthma and allergies, according to research presented at the annual meeting of the American Academy of Allergy, Asthma and Immunology in New Orleans.

   Researchers from National Jewish Health in Denver knew the existence of evidence that vitamin D insufficiency may contribute to the pathophysiology of allergic disease. They sought further information, in children, about the variables associated with vitamin D insufficiency.

   They performed a retrospective analysis of 25-hydroxy vitamin

D [25(OH)D] levels in 99 patients aged 0-18 years with asthma, atopic dermatitis, and/or food allergy. Demographic and clinical data were recorded, and multivariate linear regression was used to determine an efficient model associating demographic and clinical factors with 25(OH)D levels.

   According to the results, 56% of patients had insufficient levels of 25(OH)D (<30 ng/mL) and 17% were deficient (<20 ng/mL). In linear regression analysis, 25(OH)D levels were inversely correlated with age (P <0.0001) and number of positive environmental skin prick tests (P <0.03), but were directly correlated with FEV1/FVC ratio (P 0.04). Trends approaching significance were noted for lower vitamin D levels and higher log IgE level, latitude, and BMI. After controlling for significant demographic factors in the multivariate model (age, latitude), the presence of asthma was significantly

correlated with lower vitamin D levels (P 0.047). Amongst asthmatics, vitamin D levels were inversely correlated with taking an inhaled corticosteroid (P 0.036).

   The National Jewish Health researchers noted that the diagnosis of asthma and taking an inhaled corticosteroid were significantly correlated with lower vitamin D levels. "Future trials are needed to determine appropriate vitamin D supplementation in children and its impact on disease management," they concluded.

   A similar study presented at the meeting came from Allegheny

General Hospital in Pittsburgh. Researchers there found that vitamin D levels were reduced in children and adolescents with allergic rhinitis and asthma when compared with control subjects who had neither condition or with patients with allergic rhinitis alone.