Elevated OPG levels have also been observed within pericardium of malignant and non-malignant pericardial effusion (Karatolios et al., 2012), and there is also a positive correlation between the severity of peripheral artery disease (PAD) and plasma values of OPG (Ziegler et al., 2005). Here, TNFRSF11B is linked to peripheral arterial disease.