Comparison study of Bone Mineral Density (BMD) in native Chinese and American Caucasian populations

Abstract

Background/Objective: Osteoporosis and osteoporotic fracture risk are extraintestinal manifestations of the inflammatory bowel disease, whose etiopathogenic mechanisms have not been determined yet. Anti-tumor necrosis factor (TNF)-α are used in treatment of inflammatory bowel disease (IBD), but it is unknown if they play a role in osteoporotic fracture prevention. The objective of this study was to know if anti-TNF decreases fracture risk or modifies bone mineral density. To determine the possible risk factors associated with fractures, and assess the incidence of vertebral fractures in IBD patients. Methods: Longitudinal prospective cohort study (7 yr of follow-up); which included 71 IBD patients, 23 received anti-TNF-α; the remaining 48 received conventional treatment, constituted the control group. Patients participated in a questionnaire which gathered risk factors associated with the development of osteoporosis and fractures. Radiographs of the dorsolumbar-spine were performed and also a bone density measurement. Their biochemical and bone remodeling parameters were determined. Results: Although patients who did not receive anti-TNF-α, suffered more fractures but biologic therapy did not reduce the risk of new vertebral fractures. The increase of bone mass was significantly higher the group treated with anti-TNF-α. The increase in the lumbar spine was of 8% and in the femoral neck was of 6.7%. The only determinant factor for the incidence of vertebral fractures was a history of previous fractures (odds ratio of 12.8; confidence interval 95% 2.37–69.9; p = 0.003). The incidence of vertebral fractures in IBD patients was considerably high: 26.7/700 patient-yr. Conclusions: Anti-TNF-α, although increased bone mass in these patients, did not reduce the risk of new vertebral fractures. In this study, patients with IBD have a considerably high incidence of fractures. Only the existence of previous vertebral fractures was a predictive factor for consistent fractures.