Prospective, Randomized, Double-Blind, Parallel-Group, Comparative Effectiveness Clinical Trial Comparing a Powder Vehicle Compound of Vitamin D With an Oil Vehicle Compound in Adults With Cystic Fibrosis

Background: There is little consensus on the most efficacious vehicle substance for vitamin D supplements. Fat malabsorption may impede the ability of patients with cystic fibrosis (CF) to absorb vitamin D in an oil vehicle. We hypothesized that vitamin D contained in a powder vehicle would be absorbed more efficiently than vitamin D contained in an oil vehicle in patients with CF.

Methods: In this double-blind, randomized controlled trial, hospitalized adults with CF were given a one-time bolus dose of 100,000 IU of cholecalciferol (D) in a powder-based or oil-based vehicle. Serum D, 25-hydroxyvitamin D, and parathyroid hormone concentrations were analyzed at 0, 12, 24, and 48 hours posttreatment. The area under the curve for serum D and the 12-hour time point were also assessed as indicators of D absorption.

Results: This trial was completed by 15 patients with CF. The median (interquartile range) age, body mass index, and forced expiratory volume in 1 second were 23.7 (19.9-33.2) years, 19.9 (18.6-22.6) kg/m, and 63% (37%-80%), respectively. The increase in serum D and the area under the curve was greater in the powder group ( P = .002 and P = .036, respectively). Serum D was higher at 12 hours in the powder group compared with the oil group ( P = .002), although levels were similar between groups by 48 hours.

Conclusions: In adults with CF, cholecalciferol is more efficiently absorbed in a powder compared with an oil vehicle. Physicians should consider prescribing vitamin D in a powder vehicle in patients with CF to improve the absorption of vitamin D from supplements.