Plasma vitamin D levels and inflammation in the aortic wall of patients with coronary artery disease with and without inflammatory rheumatic disease

Objectives: Vitamin D modulates inflammation, and this may explain the observed associations between vitamin D status and disorders driven by systemic inflammation, such as coronary artery disease (CAD) and inflammatory rheumatic diseases (IRDs). The aims of this study were to assess vitamin D status in patients with CAD alone and in patients with CAD and IRD, and to explore potential associations between vitamin D status and the presence of mononuclear cell infiltrates (MCIs) in the aortic adventitia of these patients. Method: Plasma levels of 25-hydroxyvitamin D [(25(OH)D] were determined by radioimmunoassay and 1,25-dihydroxyvitamin D [1,25(OH)D] by enzyme immunoassay in the 121 patients from the Feiring Heart Biopsy Study (FHBS) who had available histology data on adventitial MCIs; 53 of these had CAD alone and 68 had CAD and IRD. Results: In the crude analysis, vitamin D levels were similar in CAD patients with and without IRD. After adjustment for potential confounders, IRD was associated with an increase of 8.8 nmol/L [95% confidence interval (CI) 1.0–16.6; p = 0.027] in 25(OH)D and an increase of 18.8 pmol/L (95% CI 4.3–33.3; p = 0.012) in 1,25(OH)D, while MCIs in the aortic adventitia were associated with lower levels of 1,25(OH)D (β = –18.8, 95% CI –33.6 to –4.0; p = 0.014). Conclusions: IRD was associated with higher levels of both 25(OH)D and 1,25(OH)D. These findings argue against the hypothesis that patients with high systemic inflammatory burden (CAD+IRD) should have lower vitamin D levels than those with less inflammation (CAD only). Of note, when controlled for potential confounders, low 1,25(OH)D levels were associated with adventitial aortic inflammation.