Altered bone metabolism in Tunisian patients with inflammatory bowel diseases

Several biochemical markers of bone remodelling and bone regulating factors were measured in 67 patients with inflammatory bowel disease (IBD), and 43 age- and sex-matched healthy subjects. Patients showed significantly higher mean levels of urinary degradation products of C-telopeptide of type I collagen (crosslaps), total alkaline phosphatase and interleukin-6, and lower mean levels of 25 OH vitamin D. Osteocalcin, calciuria and parathormone were within normal ranges. In multivariate analysis, crosslaps was associated with osteocalcin (p=0.01) and disease activity (p=0.04). Osteocalcin was associated with crosslaps and PTH (p=0.04). Crosslaps and interleukin 6 were significantly increased in IBD patients with osteoporosis. No association was found between osteoporosis and total alkaline phosphatase, osteocalcin, paratohormone and 25 OH vitamin D. Bone resorption rate was increased and was associated with osteoporosis in IBD patients. Inflammatory process, malnutrition, and hypovitaminosis D may contribute to the bone loss in IBD.