Serum Vitamin D Levels and Vitamin D Supplement in Adult Patients with Asthma Exacerbation.

Vitamin D deficiency has been linked to an increased risk of asthma exacerbations. This study aimed to compare vitamin D status during the period of severe asthma exacerbations and investigate if vitamin D supplementation improves asthma control. A total of 47 asthmatic patients and 40 healthy subjects participated in this study. Serum 25-hydroxyvitamin D (25(OH)D), asthma control test (ACT) score, and % predicted peak expiratory flow rate were evaluated in the period with and without severe asthma exacerbations. After that, we provided vitamin D2 supplements to the patients with low vitamin D levels for 3 months. At the period of asthma exacerbation, the prevalence of vitamin D deficiency and insufficiency was 38.29% and 34.04%. There was no significant difference in the levels of serum 25(OH)D with and without asthma exacerbations but the levels were significantly higher in the healthy group. Serum 25(OH)D levels significantly correlated with ACT score. Moreover, vitamin D2 supplementation improved asthma control in uncontrolled asthma group. Hypovitaminosis D was common in asthmatic patients but was not the leading cause of asthma exacerbations. Serum 25(OH)D levels correlated with the ability to control asthma. Improving vitamin D status might be a benefit in uncontrolled asthmatic patients.