Vitamin D and Severe Asthma Exacerbations

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.