The Effects of Vitamin D Supplementation on Pulmonary Function of Chronic Obstructive Pulmonary Disease Patients, before and after Clinical Trial

Vitamin D has several extra calcemic effects. Vitamin D deficiency is highly prevalent in chronic obstructive pulmonary disease (COPD) patients but little is known about it's association with lung function. OBJECTIVE To investigate whether supplementation with vitamin D could improve pulmonary function in COPD patients. DESIGN Before and after, double center, clinical trial. SETTING Hazrat Rasoul University Hospital, Tehran, and Imam Khomaini University Hospital, Ahvaz, Iran. PARTICIPANTS 24 patients with mild to very severe COPD. INTERVENTION Loading dose of 300,000-600,000 International Units (IU) of vitamin D, then 50000 IU weekly for 12 weeks. MEASUREMENTS The outcomes included forced expiratory volume in one second (FEV1), forced vital capacity (FVC), vital capacity (VC), forced expiratory flow between 25%-75% of forced vital capacity (FEF 25%-75%), exercise capacity according to the six minute walk test(6MWT) and the saturation of oxygen during exercise. RESULTS The mean FEV1 (p-value = 0.866), FVC (p-value = 0.475) and VC (p-value = 0.425) were not significantly different before and after intervention. FEF 25%-75% did not improve with this intervention (p-value = 0.555). The vitamin D supplementation did not have any significant effect on the exercise capacity (p-value=0.175) or the saturation of oxygen (p-value = 0.635). CONCLUSION Pulmonary function and exercise capacity did not improve with vitamin D supplementation in COPD patients.