TNF and Obesity: Increased circulating and tissue pro-inflammatory cytokines in obesity are involved in bone metabolism through multiple pathways.[1,7] Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) may promote osteoclast activity and bone resorption by modifying the receptor activator of NF-κB (RANK)/RANK ligand/osteoprotegerin pathway.[8,9]