Vitamin D status correlates with the markers of cystic fibrosis-related pulmonary disease.

BACKGROUND: The prevalence of Vitamin D deficiency remains high in cystic fibrosis despite daily supplementation. Vitamin D as an immunomodulator has been related to lower respiratory tract infections in children. The present study was undertaken to examine the association between vitamin D status and markers of cystic fibrosis-related pulmonary disease including exacerbations, bacterial colonization and pulmonary function.

METHODS: The study includes review of records of 51 cystic fibrosis patients. Baseline patient variables and serum vitamin D levels were recorded. Based on vitamin D levels study patients were divided into three groups: vitamin-D sufficient (≥20 ng/mL), vitamin-D insufficient (12 to 20 ng/mL), and vitamin D-deficient (≤12 ng/ml).

RESULTS: The proportion of children with deficient, insufficient and sufficient vitamin D levels were 47.1%, 15.7%, and 37.2%, respectively. Female sex, bacterial colonization and a greater number of exacerbations were associated with highest odds of developing vitamin D deficiency in patients with CF with 1.77 (0.22-4.61) (p = 0.002), 2.9(0.57-14.82) (p = 0.011), and 5.12 (1.28-20.50) (p = 0.021) respectively. The comparison of vitamin-D levels taken during exacerbations, colonization and during routine follow-up were significant [16.04 (7.42-27.91), 24.3 (15.5-32.4) and 48.54 (18.37-78.7) ng/ml, p < 0.001]. The FEV1 was determined in 24 patients; the comparison was significant between vitamin D-deficient and -sufficient groups [0.75 (0.717-0.777) vs. 0.82 (0.74-0.92) p < 0.05].

CONCLUSION: We concluded that vitamin D deficiency was highly prevalent in children with CF, despite daily supplementation of the vitamin in diet. Further, vitamin D deficiency was associated with a higher rate of pulmonary exacerbations and higher incidence of pulmonary bacterial colonization. In addition, in younger patients, low vitamin D levels were associated with reduced pulmonary function.