Association between hypovitaminosis D and frequency of pulmonary exacerbations in children and adolescents with cystic fibrosis

Objective: We evaluated the association between vitamin D levels and nutritional status, pulmonary function and pulmonary exacerbations in children and adolescents with cystic fibrosis. Methods: 25-hydroxyvitamin D (25(OH)D)levels of 37 children and adolescents were retrospectively evaluated. Pulmonary function, body mass index, height for age, and pulmonary exacerbations episodes were associated with vitamin D levels divided into two groups: sufficient (>= 30ng/mL)and hypovitaminosis (<30ng/mL). Results: Hypovitaminosis D (25(OH)D <30ng/mL)was observed in 54% of subjects. The mean level of 25(OH)D was 30.53 +/- 12.14ng/mL. Pulmonary function and nutritional status were not associated with vitamin D levels. Pulmonary exacerbations over a 2-year period (p=0.007)and the period from measurement up to the end of the follow-up period (p=0.002)were significantly associated with vitamin D levels. Conclusion: Hypovitaminosis D was associated with higher rates of pulmonary exacerbations in this sample of children and adolescents with cystic fibrosis. Hypovitaminosis D should be further studied as a marker of disease severity in cystic fibrosis. Further prospective and randomized studies are necessary to investigate causality of this association.