Associations of C-Reactive Protein to Indices of Vascular Health and the Influence of Serum 25(OH) D Status in Healthy Adults

Elevated serum high-sensitivity C-reactive protein (hs-CRP) and low serum 25-hydroxyvitamin D [ 25(OH) D] are associated with increased cardiovascular disease (CVD) risk. Ethnic differences in serum hs-CRP and 25(OH) D concentrations and CVD are known. Objectives: to investigate the ethnic differences in hs-CRP concentrations, to assess the influence of 25(OH) D on these ethnic differences and to examine the influence of 25(OH) D on association between hs-CRP and cardiovascular health indices. Subjects: 62 healthy adults [ 26 African Americans (AA), 26 European Americans (EA), and 10 Hispanic Americans (HA)], ages 18-55 years. Serum hs-CRP and 25(OH) D as well as pulse wave velocity (PWV), augmentation index (AIx), and flow-mediated dilatation (FMD) were measured. hs-CRP was inversely associated with 25(OH) D (r = -0.25, P = 0.049), and hs-CRP was positively associated with PWV (r = 0.29, P = 0.04). The association of hs-CRP with PWV attenuated after adjustment for 25(OH) D (P = 0.15). hs-CRP was higher in AA compared to EA (P = 0.05); this differences was reduced by 32% after adjusting for serum 25(OH) D. Conclusion: eventhough the inverse association between serum 25(OH) D and CRP does not infer causality, lower serum 25(OH) D may increase risk for inflammation and endothelial dysfunction. The lower 25(OH) D in AA may predispose to greater inflammation and associated vascular dysfunction.