**6.1 Pathophysiology of osteoporosis in inflammatory bowel disease**

In addition to corticosteroid use, aging, smoking, malnutrition, vitamin D and calcium malabsorption and deficiency, immobility, and the underlying inflammatory condition are risk factors for osteoporosis in inflammatory bowel disease. According to research by Bernstein et al., patients with IBD have a 40% higher incidence of fractures than the general population [41].

### **6.2 Inflammation**

Numerous factors have a significant impact on bone metabolism, but there is growing evidence that inflammation itself has a role in osteoporosis among patients with IBD. Even without the use of drugs like corticosteroids, some investigations in newly diagnosed patients with IBD showed a decline in BMD. Osteoporosis and a

increased fracture incidence are associated with a number of chronic inflammatory diseases [42–44]. The production of pro-inflammatory cytokines including interleukin-1 (IL-1), tumor necrosis factor alpha (TNF-), IL-6, IL-11, IL-15, and IL-17, is linked to increased bone resorption and decreased bone formation. RANK/RANKL/ osteoprotegerin is probably the major mechanism implicated in the onset of osteoporosis in IBD and other inflammatory illnesses. In a study of 137 IBD patients, Reffitt et al. found that those with prolonged illness remission had higher BMD [45–47].
