Background: Vitamin D deficiency is believed to play an important role in the pathophysiology of asthma. However, there has not yet been a study conducted in Thailand to examine the prevalence of vitamin D deficiency in adult asthmatic patients and its relationship with asthmatic activity.

Materials and Methods: A cross-sectional study was conducted in Thai asthmatic patients and healthy volunteers between June and October 2014 in a tertiary care setting. Age, gender, BMI, occupation, spirometry parameters, and 25-hydroxy-vitamin D levels (25(OH)D) were recorded in both groups. The authors then analyzed vitamin D status and its association with the prevalence of asthma and asthmatic activity.

Results: The present study included 72 patients with asthma and 98 controls. The prevalence of vitamin D deficiency (less than 20 ng/mL) and vitamin D insufficiency (20 to 30 ng/mL) were 8.3% and 34.7%, respectively in asthmatic patients and 6.1% and 40.8%, respectively in healthy patients. Serum 25(OH)D levels in asthmatic patients were slightly lower (32.7±10.1 ng/mL) than in controls (33.6±11 ng/mL), but without statistical significance (p=0.59). Among the asthmatic subjects, serum 25(OH)D levels were not significantly related to asthmatic activity.

Conclusion: The prevalence of vitamin D deficiency in adult Thai asthmatic patients is 8.3 percent. The authors did not detect significant differences in 25(OH)D levels between asthmatic patients and healthy subjects or between those with well-controlled versus inadequately-controlled asthma.

Keywords: Vitamin D deficiency, Prevalence, Asthma, Thai populations

Received 8 May 2019 | Revised 16 Jul 2019 | Accepted 22 Jul 2019