The frequency of low bone mineral density and its associated risk factors in patients with inflammatory bowel diseases

Objective: To detect the frequency and the predictive factors of low bone mineral density in inflammatory bowel disease (IBD) patients, so as to optimize bone mineral density (BMD) monitoring and treatment for those at risk. Subjects and methods: Thirty Asian patients were included in this study and were divided into 18 patients with ulcerative colitis (UC), and 12 patients with Crohn's disease (CD). All patients were diagnosed by colonoscopy and histopathological biopsy and were subjected to routine laboratory investigations in addition to 25 hydroxy vitamin D levels as well as serum calcium, phosphorus and alkaline phosphatise. BMD was measured by using dual-energy X-ray absorptiometry (DEXA) scan at lumbar spine and femoral neck; predictive factors for BMD were analyzed by group comparison and step-wise regression analysis. Results: There was increased frequency of osteoporosis and osteopenia involving the lumbar spine in patients with IBD being more common among CD patients than in the UC group. Positive correlations were found between low BMD measurements and vitamin D levels, body mass index (BMI) (P < 0.001) as well as steroid cumulative dose and duration of therapy (P < 0.001); stepwise regression analysis showed that CD and vitamin D deficiency are predictive factors for both osteoporosis and osteopenia (P = 0.024, P = 0.027, respectively). Conclusion: Low BMD was found to be more frequent among patients with CD than UC; in addition CD and vitamin D deficiency act as predictive factors for low BMD. We recommend that calcium and vitamin D should be given to all IBD patients; in addition, bisphosphonate administration should be put into consideration.