Abstract
Inflammatory bowel diseases (IBD) are considered to be a chronic inflammatory process of the gastrointestinal tract. The incidence of IBD worldwide varies from 0.5-24.5 /100.000 for UC and 0.1-16/100.000 habitants for Crohn disease. The incidence of IBD in western populations seems to be double compared with population from Middle East. (Annual incidence rates in western populations are for CD patients 6.5/100.000, and for UC patients 10.8/100.000, while in populations in Asia the annual incidence rates for Crohn disease is 3.1/100.000 and for UC 4.1/100.000 habitants respectively). It is well known that IBD patients present low bone mineral density (BMD) and they show an increased risk of osteoporotic fractures, 40% higher than the general population which is increased with age. The pathogenetic mechanism of osteoporosis is multifactorial in IBD patients and only partially understood. Some of the factors that affect the homeostasis of calcium and bone remodeling are the chronic inflam ...
Inflammatory bowel diseases (IBD) are considered to be a chronic inflammatory process of the gastrointestinal tract. The incidence of IBD worldwide varies from 0.5-24.5 /100.000 for UC and 0.1-16/100.000 habitants for Crohn disease. The incidence of IBD in western populations seems to be double compared with population from Middle East. (Annual incidence rates in western populations are for CD patients 6.5/100.000, and for UC patients 10.8/100.000, while in populations in Asia the annual incidence rates for Crohn disease is 3.1/100.000 and for UC 4.1/100.000 habitants respectively). It is well known that IBD patients present low bone mineral density (BMD) and they show an increased risk of osteoporotic fractures, 40% higher than the general population which is increased with age. The pathogenetic mechanism of osteoporosis is multifactorial in IBD patients and only partially understood. Some of the factors that affect the homeostasis of calcium and bone remodeling are the chronic inflammation, vitamin D deficiency, smoking, use of steroids, and low BMI. There are indications that low BMD is not in direct proportion with the fracture risk, fact that underlines the necessity of finding more risk factors for the evaluation of osteoporotic facture risk. WHO has recently developed FRAX score, which is an algorithm for the evaluation of fracture risk based on clinical factors considering or not the measurement of BMD. This algorithm was calculated based on population cohort studies and provides two basic results. Firstly, the 10-year probability of a major osteo- porotic fracture (clinical spine, hip, forearm or shoulder), and secondly, the 10-year probability of a hip fracture alone. The algorithm is available through the web at: http://www.shef.ac.uk/FRAX/index.Body mass index (BMI) is negatively correlated with high fracture rates and bone mineral density (BMD) is positively correlated with increased fat mass. It has been hypothesized that these associations could probably be caused by the action of hormone-like substances called adipocytes derived directly from the fat tissue. Experimental data in rats showed that chemerin, visfatin και vaspin have an impact on BMD with different mechanisms. More specifically, inhibition of chemerin or CMKLR1 receptor influences negatively osteoblastogenesis and bone mineralization and also has an inhibitory action in osteoclastogenesis. Visfatin has been shown to stimulate the proliferation of osteoblasts in a dose dependent fashion and also to block osteoclast differentiation by suppressing RANK, NFATc1 and cathepsin K expression [19]. Recent data showed that vaspin has also a double sword action as it inhibits the RANKL-induced osteoclastogenesis and promotes osteoblastogenesis due to the suspension of the apoptosis of osteoblasts. Aim of the present study was:- To find the incidence of osteoporosis in IBD Greek patients.- To evaluate the accuracy of pre-BMD FRAX score in Greek IBD population in order to identify the patients who need medical therapy, scanning with DXA, or just close follow-up/reassurance. We also evaluated and compared the fracture risk in patients with Crohn’s disease (CD) and ulcerative colitis (UC).106- To investigate the role of fat mass and adipocytes chemerin, visfatin, and vaspin in the development of osteoporosis in IBD patients.Reduced BMD was found in 73 (61%) IBD patients, of whom 48 (40%) had osteopenia and 25 (21%) osteoporosis. Osteoporotic patients had a significantly lower total fat mass than the osteopenic patients and the patients with normal BMD (OR: 0.89, 95%CI 0.83-0.95 p=0.01). The median 10-year probability of a major osteoporotic fracture for IBD patients based on clinical data was 7.1 %, and including the BMD was 6.2 %. A significant overestimation with the first method was found (P = 0.01). Both scores with and without BMD were significantly higher in CD patients compared with UC patients (P = 0.02 and P = 0.005, respectively).Serum chemerin was higher in IBD patients than HC (CD: 13.67.1±5.8, UC: 13.9±4.3 vs. HC: 7.8±2.6 ng/mL, OR 0.95, 95%CI 0.93-0.98, P<0.0001). Serum visfatin levels in CD patients were significantly higher than UC patients (9.3±14.01 vs. 6.5±7.2 ng/mL, OR 0.86, 95%CI 0.80 -0.92, P=0.039). In multivariate logistic regression analysis, a significant independent association of osteoporosis (T-score ≤2.5 SD) with age (OR 1.04, 95%CI 1.01-1.08, P=0.02), visfatin (OR 0.78, 95%CI 0.63-0.97, P=0.02), and chemerin levels (OR 0.83, 95%CI 0.70-0.98, P=0.03) but not with body mass index or body composition wasfound.The results of the present study illustrate the impact of adipocytes action on the BMD of Greek IBD patients, as well as the great importance of predicting the risk of a major osteoporotic fracture, using FRAX algorithm. So though these results, the important role of white adipose tissue regarding the osteoporotic status of IBD patients is revealed, offering an opened field for further investigations.
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