vitamin d and severe asthma exacerbations

Conditions: Asthma

Summary: this study of vitamin d is designed to assess both the safety and efficacy of potential doses (2,000 iu/day and 4,000 iu/day) in raising a vitamin d level to a normal range in a short period of time (e.g. 4 weeks or less) compared to 200 iu/day. in children with vitamin d insufficiency or deficiency who are at risk for severe asthma exacerbations, we hypothesize that both vitamin d supplementation with 4,000 iu/day and 2,000 iu/day will safely achieve normal vitamin d levels, but that the higher dose (4,000 iu/day) will result in a larger proportion of subjects achieving this level at 4 and 8 weeks.

asthma is a major public health problem in the united states and worldwide. severe disease exacerbations account for the majority of costs attributable to asthma in the united states. vitamin d is an essential nutrient with significant immuno-modulatory effects. the observation that vitamin d insufficiency and asthma share risk factors such as urban residence, obesity, and african american ethnicity has generated significant interest in exploring a link between these two conditions. this is an 8-week randomized, double-masked, controlled trial of vitamin d3 (2,000 iu/day and 4,000 iu/day) to achieve vitamin d sufficiency (a serum 25(oh)d ≥30 ng/ml in 60 school-aged children (ages 6 to 14 years) who have vitamin d insufficiency (a serum 25(oh)d \<30 ng/ml) and are at risk for severe asthma exacerbations, but whose asthma that is well-controlled on medium-dose inhaled corticosteroid (ics) at the end of a 4-week run-in period.

Eligibility criteria:
inclusion criteria: * be at least 6 years of age and younger than 15 years of age * have physician-diagnosed asthma * taking a medium dose of ics (e.g. fluticasone 220mcg bid) for daily asthma control for at least 6 months in the prior year. * have had a severe asthma exacerbation in the previous year, defined as an emergency department (ed) visit, hospitalization, or unscheduled clinic visit for asthma resulting in intramuscular, intravenous, or oral steroids. * have bronchodilator responsiveness (bdr, an increase in fev1 ≥12% from baseline after administration of inhaled albuterol) or (if no bdr) increased airway responsiveness to methacholine challenge * have vitamin d insufficiency (a serum vitamin d (25(oh)d) level \<30 ng/ml) * have his/her parents give voluntary written consent to participate in the study exclusion criteria: * chronic respiratory disorder other than asthma (e.g., bronchiectasis). * severe asthma, as evidenced by any of the following: a) chronic need for medication other than single controller therapy and inhaled β2-agonist, b) intubation for asthma at any time, and c) ≥2 hospitalizations or ≥6 severe asthma exacerbations in the previous year * history of cigarette smoking in the prior year or former smoking if ≥5 pack-years * hepatic or renal disease, metabolic rickets, malabsorptive disorders, or other chronic diseases that would affect vitamin d metabolism * immune deficiency, cleft palate or down's syndrome, which might increase the child's likelihood of respiratory infections * treatment with anticonvulsants or pharmacological doses of vitamin d (≥1,000 iu/day of vitamin d2 or d3) * chronic oral corticosteroid therapy * inability to perform acceptable spirometry * use of investigational therapies or participation in clinical trials 30 days before or during the duration of the study * serum calcium \>10.8 mg/dl * serum 25(oh) d \<10 ng/ml (severe vitamin d deficiency)

Keywords: asthma vitamin d