TNFSF11 and periodontal disorder: Patients with DM displayed lower RANKL:OPG ratio, which would suggest that they are not susceptible for increased bone resorption via that specific pathway. However, lower levels of osteocalcin (a marker for bone formation) were also observed in patients with DM. It is suggested that this causes an insufficient repair response following bone loss, explaining the susceptibility for periodontal disease progression often seen in patients with DM.