Impact of vitamin D on spirometry findings and quality of life in patients with chronic obstructive pulmonary disease: a randomized, double-blinded, placebo-controlled clinical trial

COPD is an irreversible chronic illness with airflow limitation. The aim of the current study was to assess the role of vitamin D(3) on quality of life and pulmonary function in patients with COPD. A randomized, double-blinded clinical trial was conducted in 63 patients with COPD. Patients were placed into intervention and placebo groups. Each individual in the intervention group took 50,000 IU vitamin D(3)once a week for 8 weeks and then once a month for 4 months. There was no significant difference among FEV(1), FEV(1)/FVC, and number of exacerbations in patients with COPD (P>0.05). In the intervention group, a significant difference was observed in quality of life at 2 months (P<0.001) and 6 months (P<0.001). In addition, qualitative analysis showed that the status of exacerbation had not got worse six months after initiation in the intervention group. The current study shows that consumption of 50,000 IU vitamin D(3), as a convenient supplementation in a daily diet, is able to increase quality of life in patients with COPD.