Low vitamin K status in adults with cystic fibrosis is associated with reduced body mass index, insulin secretion, and increased pseudomonal colonization.

Patients with cystic fibrosis (CF) are at high risk of fat-soluble vitamin deficiencies, even with supplementation. The contribution of a suboptimal vitamin K status to respiratory and endocrine pathophysiology in CF has been inadequately characterized. This is a cross-sectional study in adult CF patients (≥18 years old) from the Montreal Cystic Fibrosis Cohort. Vitamin K1 (VK1) was measured with high-performance liquid chromatography, using fasted serum samples collected during an oral glucose tolerance test (OGTT: 2 h with plasma glucose and insulin every 30 min) (n = 168). Patients were categorized according to VK1 status (suboptimal defined as <0.30 nmol/L). Suboptimal VK1 levels were observed in 66% of patients. Patients with a suboptimal VK1 status have a higher risk of colonization with Pseudomonas aeruginosa (p = 0.001), have lower body mass index (BMI) (p = 0.003), and were more likely to have exocrine pancreatic insufficiency (p = 0.002). Using an established threshold for VK1, we did show significantly reduced OGTT-derived measures of insulin secretion in patients with a VK1 status below 0.30 nmol/L (first- and second-phase area under the curve (AUC)INS/GLU (p = 0.002 and p = 0.006), AUCINS (p = 0.012) and AUCINS/GLU (p = 0.004)). Subclinical vitamin K deficiency is more common than other fat-soluble vitamin deficiencies in patients with CF. We demonstrate an association between a suboptimal VK1 status and measures of insulin secretion. We highlight the potential associations of mild vitamin K deficiency with pseudomonal colonization and lower BMI, although these need to be validated in prospective studies.

Vitamin D3 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.