Serum Vitamin D Levels and Severity of Asthma in Children

Introduction: Asthma is a common chronic disease and it is a cause of attending the emergency department, hospitalization, and school absences in children. Several studies recorded in various countries report the increased prevalence of about 50% per decade for childhood asthma. Vitamin D is an essential vitamin which has effects on function of the immune system. There are Different and conflicting studies about the association between low concentration of vitamin D levels and severity of asthma in children.

The aim of this study was to assess the relationship between serum vitamin D status and childhood asthma.

Materials and Methods: In this analytical cross-sectional study, 134 children of 3-14 years old with asthma, who were hospitalized in 2014 in Madani Hospital in Khorramabad city, were investigated with regard to their age, gender, BMI, the use of inhaled corticosteroids, and serum levels of 25-Hydroxy Vitamin D. The variables and their possible association with vitamin D deficiency in patients were investigated, using the collected data from the questionnaires and laboratory exams.

Findings: Mean age of the hospitalized children was 6.76±2.8 year. Mean serum vitamin D levels in children with asthma was, 58.8±24.7 mg/dL, regardless of its severity. Among all of the children with moderate persistent asthma, 13 subjects (52%) have had vitamin D deficiency and in children with mild persistent asthma, this value was 17.1%. In addition, 1.5% of the children with intermittent asthma have had serum vitamin D deficiency. According to Fisher's exact test, the difference in the frequency distribution of serum vitamin D status in children with asthma based on the severity of asthma was significant statistically (Pv<0.0001). In spite of lower serum vitamin D in obese and over-weighted children relative to the children with normal and low BMI, this difference was not statistically significant using one-way analysis of variance.

Conclusion: In higher severities of asthma, vitamin D deficiency is more evident. Therefore, sufficient amounts of vitamin D supplementation may be effective in reducing the severity of asthma in children.