Vitamin D deficiency parallels inflammation and immune activation, the Ludwigshafen Risk and Cardiovascular Health (LURIC) study

Background: Low vitamin D concentrations are detected in patients suffering from various clinical conditions which are characterized also by inflammation and immune activation. We investigated whether vitamin D levels in patients with coronary artery disease (CAD) are related to markers of immune activation. Methods: Serum concentrations of 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] and the immune activation markers neopterin and high sensitivity C-reactive protein (hsCRP) were measured in 2015 patients derived from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study, a cohort study among patients referred for coronary angiography. Results: Serum concentrations of 25(OH)D and 1,25(OH)(2)D did not differ between patients with CAD [mean +/- SD: 25(OH)D: 17.4 +/- 9.4 mu g/L; 1,25(OH)(2)D: 34.4 +/- 13.3 ng/L] and controls [25(OH)D: 18.4 +/- 11.7 mu g/L; 1,25(OH)(2)D: 35.3 +/- 12.7 ng/L; Welch's t-test: p=n.s.] but CAD patients had higher neopterin (8.6 +/- 7.4 nmol/L) and hsCRP (9.6 +/- 19.6 mg/L) concentrations compared to controls (neopterin: 7.5 +/- 4.8 nmol/L; p = 0.0004; hsCRP: 5.4 +/- 10.0 mg/L; p<0.0001). There was an inverse correlation between serum 25(OH)D or 1,25(OH)(2)D concentrations and serum neopterin [Spearman's rank correlation: 25(OH)D: r(s) = -0.183; 1,25(OH)(2)D: rs = -0.230] and hsCRP [25(OH)D: rs = -0.142; 1,25(OH)(2)D: rs = -0.130; all p<0.0001] concentrations. Conclusions: Our results indicate increased inflammatory processes in patients with low vitamin D status. Further studies should clarify the underlying mechanisms for the observed associations of vitamin D status and inflammatory parameters.