TNFRSF11B and diabetes mellitus: Although serum OPG and TRAIL levels appeared to be regulated in vascular diseases but not in diabetes (Figs. 1 and 2), it is hard to exclude the possibility of a relationship between serum OPG and TRAIL levels and diabetes because serum OPG was significantly regulated in the “ABI below 0.9 and DM” group (Fig. 1).