Moberg, M.2; Ringbaek, T.2; Roberts, N. B.2; Vestbo, Jørgen3
1 Lung Medicine, Department of Clinical Research, Det Sundhedsvidenskabelige Fakultet, SDU2 unknown3 Lung Medicine, Department of Clinical Research, Det Sundhedsvidenskabelige Fakultet, SDU
It has been suggested that identifying phenotypes in chronic obstructive pulmonary disease (COPD) might improve treatment outcome and the accuracy of prediction of prognosis. In observational studies vitamin D deficiency has been associated with decreased pulmonary function, presence of emphysema and osteoporosis, upper respiratory tract infections, and systemic inflammation. This could indicate a relationship between vitamin D status and COPD phenotypes. The aim of this study was to assess the association between vitamin D levels and COPD phenotypes. In addition, seasonality of vitamin D levels was examined. A total of 91 patients from a Danish subpopulation of the "Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points" cohort took part in a biomarker substudy. Vitamin D concentration was measured from blood samples taken at two visits, approximately 6 months apart. The participants were 40-75-year-old patients with COPD and had a smoking history of > 10 pack-years. Fifty-six patients had 25-hydroxyvitamin D measured from blood samples from both visits. In the final model of the multivariate analyses, the factors that were associated with vitamin D deficiency at the first visit were age (OR: 0.89, p = 0.02) and summer season (OR: 3.3, p = 0.03). Factors associated with vitamin D level also at the first visit were age (B: 0.9, p = 0.02) and 6 min walking distance (B: 0.05, p = 0.01). Vitamin D was not associated with COPD phenotypes and season did not seem to be a determinant of vitamin D levels in patients with moderate to severe COPD.