Role of Vitamin D in Asthma Control: A Cross-Sectional Study of the Indian Adult Population

Background Bronchial asthma is a major health problem both globally and in developing countries like India. This heterogenous disease is characterised by chronic airway inflammation and hyperresponsiveness to various extrinsic and intrinsic stimuli. The innate and adaptive immune mechanisms play an important role in the pathogenesis of asthma. Vitamin D through its immunomodulatory function on innate and acquired immunity can affect asthma control and its exacerbation. In this study, serum levels of vitamin D in bronchial asthma patients were determined, and their correlation with asthma symptom control and exacerbation was studied. Materials and methods Serum vitamin D levels of patients diagnosed with bronchial asthma (based on their history and reversible obstruction in spirometry) who reported for follow-up at the Respiratory outpatient department of a tertiary care hospital in Western Maharashtra, India, were tested after obtaining informed consent. A questionnaire was given to assess their asthma control and exacerbations. Based on their symptom control over the past four weeks, they were categorized into well-controlled (WC), partially controlled (PC), and uncontrolled (UC) asthma groups. Results Serum vitamin D levels were determined for 70 patients diagnosed with asthma, of which 10 patients fell into the UC group, 28 into the PC group, and 32 into the WC group. Among the 10 patients in the WC group, vitamin D levels were deficient in six (60%) patients, insufficient in two (20%) patients, and normal in two (20%) patients. Among the 28 patients in the PC group, vitamin D levels were deficient in 19 (67%) patients, insufficient in seven (25%) patients, and normal in two (7.1%) patients. Among the 32 patients in the UC group, vitamin D levels were deficient in 17 (53.1%) patients, insufficient in 10 (31.2%) patients, and normal in five (15.6%) patients. Conclusions Although vitamin D deficiency was highly prevalent among Indian adult asthma patients, there was no statistically significant relationship between serum vitamin D levels and asthma control.