Vitamin D 3 supplementation among adult patients with cystic fibrosis.

BACKGROUND & AIMS: Vitamin D (Vit D) deficiency in cystic fibrosis (CF) is partially secondary to exocrine pancreatic insufficiency. Our aim was to establish a Vit D3 supplementation protocol that will increase 25(OH)D to the recommended level (30 ng/mL).

METHODS: Retrospective study of 200 patients (≥18 years) conducted from February 2007 to June 2014 at the CF clinic of the Centre Hospitalier de l'Université de Montréal. Vit D3 supplementation protocol was 1600 IU/day or 10,000 IU/week during the summer (May 1st to October 31st) and 3200 IU/day or 20,000 IU/week during the winter (November 1st to April 30th), in addition to the 1200 IU/day included in multivitamins.

RESULTS: Significant increase in serum 25(OH)D levels from baseline (25.9 ± 10.3 ng/mL) to follow-up (37.0 ± 11.4 ng/mL) (P ≤ 0.001). At follow-up, increased doses during the winter improved serum 25(OH)D levels to a degree comparable to the summer.

CONCLUSIONS: This supplementation protocol is efficient and needs to be tested in other CF adult cohorts and correlated to potential health benefit measurements.