Less data and conflicting results still exist in what regards the association between another group of mediators, such as osteoprotegerin (OPG) [10], the receptor activator of nuclear factor-kappa B ligand (RANKL) [12], or dickkopf-1 (DKK-1) [13], and the development of CVD in RA. The gene discussed is DKK1; the disease is rheumatoid arthritis.