Bone Mineral Density in Patients with Newly Diagnosed Inflammatory Bowel Disease: Frequency and Risk Factors in Tunisian Population. Results of a Prospective Study

Background and Aims: Osteopenia and osteoporosis are frequently encountered with Inflammatory Bowel Disease (IBD). Our aims were to determine the prevalence of low bone mineral density (BMD) in patients with recently diagnosed IBD, and to assess predictive factors of reduced BMD. Patients and Methods: Prospective study conducted from January 2008 to December 2012 and involved patients with IBD treated in the Department of Gastroenterology of the Internal Security Forces Hospital. The data collected included: age, gender, body mass index (BMI), diagnostic delay, disease activity, and disease localization. Laboratory findings included serum calcium, phosphate, albumin, hemoglobin, and C-reactive protein. BMD was assessed by dual energy X-ray absorptiometry (DEXA) of the lumber spine and femoral neck. According to WHO criteria, osteopenia was defined as a T-score between -1 and -2 SD, and osteoporosis as a T-score less than -2 SD. Results: A total of 34 patients (17 men, 17 women) were enrolled. Mean age was 37.1 ± 13.8 years (range 16 - 62). Twenty-two patients (65%) had Crohn’s disease (CD) and 12 patients (35%) had ulcerative colitis (UC). Mean BMI was 20.5 ± 4 kg/m2. Low BMD occurred in 50% of patients (12 CD, 5 UC). Thirteen patients (38.2%) exhibited osteopenia and 4 patients (10.8%) showed osteoporosis. Mean vertebral T-score was -0.933 ± 1.41 (range -4.1 to 1.7) and BMD in this site was 1.079 ± 0.17 g/cm2 (range 0.674 to 1.380). Mean femoral T-score was -0.398 ± 1.2 (range -3.1 to 2.4) and BMD in this site was 0.990 ± 0.173 g/cm2 (range 0.633 to 1.600). There was a positive correlation between T-score and albuminemia. Low BMI was found to be predictive factor of reduced BMD at the moment of IBD diagnosis. However, no correlation was found between BMD and the other studied variables (age, gender, smoking, history of fracture, disease location, duration of disease, activity, small bowel resection, serum calcium level, phosphate, C-reactive protein and hemoglobin). Conclusion: Our study showed that the half of patients with IBD had a low BMD in newly diagnosed IBD patients. Low BMI and hypoalbuminemia were the major factors affecting BMD in these patients. Bone density measurement should be performed in all patients with IBD in an early stage of the disease.