Association Between Serum 25-hydroxyvitamin D Level and Pulmonary Exacerbations in Cystic Fibrosis

Objective: To identify effects of vitamin D status, as defined by circulating 25-hydroxyvitamin D (25-OHD) levels on the annual frequency of pulmonary exacerbations (Pex) and hospitalizations, on standard measures of pulmonary function, and to identify determinants of 25-OHD levels in pediatric patients with cystic fibrosis (CF).

Hypothesis: Higher levels of serum 25-OHD would be associated with fewer Pex and hospitalizations, and improved lung function based on pulmonary function tests (PFTs).

Study Design: Retrospective chart review of 53 pediatric patients from January 2011 to December 2011. Significant relationships were examined using linear and logistic regression analyses.

Patient Selection: Patients ages 5 through 22 years followed at the CF Care Center and Clinic at Yale-New Haven Hospital, New Haven, CT., who had at least four clinic visits and at least one 25-OHD measurement between January 1, 2011 and December 31, 2011.

Results: Serum 25-OHD level and gender were strong independent determinants of the annual number of Pex (P < 0.01, with lower 25-OHD level and female gender associated with Pex). There was a significant influence of gender (P < 0.05) and a near-significant influence of serum 25-OHD (P < 0.08) on hospitalization rate. There was no effect of 25-OHD levels on PFTs. Other candidate factors (age, season, gender, pancreatic sufficiency, or severity of genetic mutation) did not significantly effect 25-OHD level.

Conclusions: The annual number of Pex in pediatric CF patients is significantly associated with 25-OHD levels and gender, raising the consideration that maintaining vitamin D sufficiency may lead to decreased incidence of Pex and hospitalizations requiring antibiotic therapy.