Cholecalciferol Supplementation in Strengthening Inspiratory Muscles in Cholecalciferol-Deficient Patients With Chronic Obstructive Pulmonary Disease

Inclusion Criteria:

Current or ex-smoker with at least a 10-year pack history
COPD, defined as forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) < 70% and FEV1% predicted < 80%
25-hydroxy vitamin D3 (25[OH]D3) level less than 20 ng/mL prior to study initiation
Willingness to comply with study guidelines
Willingness to avoid alternative/additional vitamin D3 supplementation for the duration of the trial
Subject must understand the investigational nature of this study and sign an Independent Ethics Committee/Institutional Review Board approved written informed consent form prior to receiving any study related procedure

Exclusion Criteria:

Personal history of lung cancer or head and neck cancer
History of malabsorption syndrome (e.g., pancreatic insufficiency, celiac disease, or tropical sprue)
History of known thyroid disease
History of known sarcoid disease
History of known abnormalities in calcium metabolism
Hypercalcemia (serum calcium in excess of laboratory upper limit normal [ULN])
Self-reported consumption of more than 4 alcoholic drinks per day
Use of anti-seizure medications phenobarbital or phenytoin, which can disrupt vitamin D metabolism
History of known renal dysfunction
History of known nephrolithiasis (kidney stones)
Current use of supplemental oxygen
Inability to exercise due to musculoskeletal issue, osteoarthritis or underlying cardiac disease
Current participation in a cancer intervention prevention study, except for smoking cessation
Any condition which in the Investigator's opinion deems the subject an unsuitable candidate to receive study drug
Inability to swallow pills
Vitamin D supplementation > 2,000 IU/day of vitamin D within 30 days prior to enrollment
Positive Pregnancy Test