TNF and osteoporosis: First, inflammatory cytokines (e.g., interleukin-1 (IL-1), and interleukin-6 (IL-6), tumor necrosis factor-alpha (TNFα)) associated with chronic HBV infection can increase receptor activator of nuclear factor kappa-B ligand (RANKL) to stimulate osteoclastogenesis and bone resorption.13 Moreover, TNFα was reported to inhibit the osteoblast differentiation and promote osteoblast apoptosis.13 The combined effects of these inflammatory cytokines can result in bone formation decreasing and bone resorption increasing, leading to reduced bone mineral density and then causing osteoporosis.