Bone mineral density and body composition in patients with ulcerative colitis

Risk of fracture and low bone mineral density in adults with inflammatory bowel diseases. A systematic literature review with meta-analysis

Inflammatory bowel diseases (IBDs) are associated with a decreased bone mineral density, but the impact on fractures is unknown. In our study, global risk of fracture is increased for patients with IBDs versus controls. This result will help to determine the appropriate assessment with early screening and management of osteoporosis. Inflammatory bowel diseases (IBDs), such as Crohn's disease (CD) and ulcerative colitis (UC), are associated with a decreased bone mineral density (BMD). However, the impact on fracture risk is unknown and data are contradictory across studies. In this systematic review and meta-analysis, we aimed to assess the risk of fracture and presence of low BMD in patients with IBDs compared to healthy controls. A systematic search of literature was conducted of MEDLINE, EMBASE, the Cochrane library and abstracts from appropriate scientific congresses. Studies were selected if they compared the incidence of fractures and/or BMD measurement by dual-energy X-ray absorptiometry in patients with IBDs and healthy sex- and age-matched controls. Data were extracted by two independent investigators. Meta-analysis was performed with the inverse variance approach to estimate pooled odds ratios (ORs) and risk ratios (RRs) with their 95% confidence intervals (CIs). Twenty-four studies met the inclusion criteria. On the basis of nine studies, global risk of fracture was increased for patients with IBDs versus controls (RR = 1.38, 95% CI 1.11-1.73; p = 0.005). Fracture risk with IBDs was significantly increased for vertebral fractures (OR = 2.26, 95% CI 1.04-4.90; p < 0.001), but not for any other site. The analysis of 16 studies evaluating BMD showed a significant decrease in mean BMD and Z-scores for IBD patients versus controls at all sites. In our meta-analysis, patients with IBDs have an increased risk of fractures, especially in the spine, and significant decreased BMD at all sites, which suggests the need for identifying high-risk individuals among this population.

The bone and fat connection in inflammatory bowel diseases

Osteopenia and osteoporosis are common manifestations in inflammatory bowel diseases (IBD) but the pathogenetic mechanism of bone loss in IBD is only partially understood. There is evidence that fat mass is an important determinant of the bone mineral density and adipose-derived factors seem to play an important role for the association between fat mass and bone mass. The association between adiposity and low bone density is rather poorly studied in IBD, but emerging data on adipokines in IBD in relation to osteoporosis provide a novel pathophysiological concept that may shed light on the etiology of bone loss in IBD. It could be suggested that adipokines interfere in bone metabolism by altering the sensitive balance between osteoblasts and osteoclasts although further studies in this setting are needed.

Systematic review: body composition in adults with inflammatory bowel disease

BACKGROUND

There is a paucity of data on body composition in patients with inflammatory bowel disease (IBD). Alterations of fat and muscle may affect bone health, muscle performance, quality of life (QoL) and overall morbidity.

AIMS

To systematically review the literature on body composition in adults with IBD, and to discuss potential contributory factors and associations.

METHODS

A systematic search was performed in July 2012 of OVID SP MEDLINE, OVID EMBASE and National Library of Medicine's PubMed Central Medline (Limitations: English, humans, from 1992). A total of 19 articles comparing body composition in patients with IBD with healthy age- and sex-matched control populations were included in the primary analysis.

RESULTS

A total of 631 patients with Crohn's disease (CD) and 295 with ulcerative colitis (UC), mean age 37.1 (s.d. ± 9.2) years; 485 (52%) female, were reported upon. Data were heterogeneous and methodology varied. Compared with controls, a statistically significant reduction in body mass index (BMI) was reported in 37% of CD and 20% of UC patients; reduced fat-free mass in 28% CD and 13% UC patients, and reduced fat mass in 31% CD and 13% UC patients. There was no consistent association between body composition and disease activity, duration, extent or therapies. BMI did not accurately predict body composition.

CONCLUSIONS

Current data, although heterogeneous, suggest that many patients with IBD are affected by aberrations in fat and lean mass, which may not be detected during routine clinical assessment. The prevalence and impact of altered body composition amongst this population warrant further investigation.

Polymorphisms of the macrophage inflammatory protein 1 alpha and ApoE genes are associated with ulcerative colitis

BACKGROUND AND AIMS

An increased production of macrophage inflammatory proteins 1 alpha (MIP-1alpha) has been reported to be associated with ulcerative colitis (UC). We investigated whether a polymorphism site in MIP-1alpha was associated with UC in a Chinese population. Additionally, considering the abnormal lipoprotein metabolism in subjects with UC, we also sought to determine whether genetic variation in the apolipoprotein E (ApoE) gene may play a role in the development of UC.

MATERIALS AND METHODS

We examined the MIP-1alpha -906 (TA)(4)/(TA)(6) polymorphism and the ApoE polymorphism in a cohort of 162 unrelated UC patients and 220 healthy controls by using restriction fragment length polymorphism assay.

RESULTS

A significantly increased frequency of the MIP-1alpha -906 (TA)(6)/(TA)(6) genotype (P = 0.0031, odds ratio [OR] = 1.851, 95% confidence interval [CI] 1.228-2.791), as well as of the ApoE epsilon4+ genotype (P < 0.001, OR = 2.869, 95% CI 1.768-4.657), in patients with UC was proven. Moreover, the carriage of both MIP-1alpha -906 (TA)(6)/(TA)(6) genotype and ApoE epsilon4+ genotype confers greater risk for the development of UC (P < 0.001, OR = 5.432, 95% CI 2.761-10.689).

CONCLUSION

These findings suggest that variation in the MIP-1alpha and ApoE genes and their interaction may increase susceptibility to UC. Identifying these novel susceptibility genes, as well as their interactions, will help our understanding of the disease mechanisms of UC and may identify targets for developing novel treatment measures.

The pathophysiology of bone disease in gastrointestinal disease

Reduced bone mass and the increased risk of fracture in gastrointestinal diseases have a multifactorial pathogenesis. Undoubtedly, genetics play an important role, but other factors such as systemic inflammation, malnutrition, hypogonadism, glucocorticoid therapy in inflammatory bowel disease (IBD) and other lifestyle factors, such as smoking or being sedentary, may contribute to reduced bone mass. At a molecular level the proinflammatory cytokines that contribute to the intestinal immune response in IBD and probably also in coeliac disease are also known to enhance bone resorption. The discovery of the role of the receptor to activated NFkappaB (RANK) interaction with its ligand RANKL in orchestrating the balance between bone resorption and formation may link mucosal and systemic inflammation with bone remodelling, since RANK-RANKL are also involved in lymphopoiesis and T-cell apoptosis. Low circulating leptin in response to weight loss in any gastrointestinal disease may be an important factor in reducing bone mass. This report will summarize current concepts regarding gastrointestinal diseases (primarily IBD, coeliac disease and postgastrectomy states) and low bone mass and fracture.