RESUMO
BACKGROUND: Vitamin D deficiency is common in CF. Whether vitamin D affects pulmonary function in CF is unknown. METHODS: Data were abstracted from clinically stable CF patients who had pulmonary function studies and serum 25-hydroxyvitamin D [25(OH)D, ng/ml] levels drawn within 2 months of each other. Findings were adjusted for multiple variables known to affect pulmonary function in CF. RESULTS: Enrollees totaled 597. Overall mean 25(OH)D level was 29.6±12.8 ng/ml (SD). Serum 25(OH)D levels showed a significant correlation with forced expiratory volume in 1s (FEV1) % predicted (r=0.20, p<0.0001) and forced vital capacity % predicted (r=0.13, p=0.0019). Multivariate analysis revealed that serum 25(OH)D remained an independent predictor of FEV1 % predicted even after controlling for multiple other factors known to affect CF lung function. CONCLUSIONS: Serum 25(OH)D levels are significantly associated with pulmonary function in CF. Further study is required to determine whether this association is causal.
