Role of vitamin D supplementation in lung function testing and exercise capacity

Introduction: Vitamin D deficiency is rising global public health problem, and low level of vitamin D has been linked to many diseases including respiratory diseases. Chronic obstructive pulmonary disease (COPD) is characterized by chronic airflow limitation due to inhalation of noxious particles or gases such as cigarette smoke and biomass fuel exposure. Airway inflammation is predominant feature in COPD: With disease progression, FEV1 declines. No treatment has yet been proven to inhibit COPD progression except smoking cessation. The aim of this study is to evaluate the role of vitamin D supplementation in improving lung function and exercise capacity in COPD patients. Material and Method: This study was conducted at a tertiary care hospital of Northern India. Vitamin D deficiency is defined as levels < 30ng/ml. All patients with deficient vitamin D level were supplemented with 600,000 IU of vitamin D orally for 12 weeks. Pulmonary Function Test and Exercise capacity were tested before and after vitamin D supplementation. Result: Out of 118 consecutive COPD patients included in the study, 84 patients had vitamin D level<30 ng/ml. According to GOLD criteria, 12 patients were in mild COPD group, 30 patients were in moderate COPD groups, 50 patients were in severe COPD group and 26 patients were in very severe COPD group. Paired t-test analysis showed no significant improvement in FEV1 (p= 0.762), FVC (p=0.554) or FEV1/FVC(p=0.616) after vitamin D supplementation. There was no significant improvement in Six Minute Walk distance after vitamin D supplementation. Conclusion: Vitamin D supplementation has no effect on Pulmonary Fuunction Test or Exercise capacity in COPD patients.