Study Examines Whether Inflammatory Bowel Disease Can Lead to Osteoporosis
Patients who have inflammatory bowel disease (IBD) are at a higher risk of developing osteoporosis and osteoporosis-related fractures. But most studies about IBD and bone mineral density (BMD) are from selected referral centers, and they do not describe exactly what aspects of IBD can lead to osteoporosis.
Canadian researchers set out to investigate this relationship.
Results of the study were published in the paper “The relationship between inflammatory bowel disease and bone mineral density. Results of a population-based study.” The paper was presented at the 2011 Annual Meeting of the American Society of Bone and Mineral Research.
Researchers used 2 databases: the University of Manitoba IBD Epidemiologic Database and the Manitoba BMD Database. These databases used in the study virtually captured all people living in Manitoba, Canada, who have IBD and all people who have had dual x-ray absorptiometry (DXA).
For this study, 45,714 patients underwent baseline BMD testing between 1997 and 2008. Study participants were 20 years old or older.
Out of all the study participants, 1,230 patients had IBD.
Using DXA, BMD was measured at the lumbar spine (L1-L4), total hip, femoral neck, and greater trochanter.
For the purposes of this study, multivariate linear regression and logistic regression were performed to determine the independent effect of an IBD diagnosis on T-scores and on the likelihood of having an osteoporotic T-score (<-2.5) at each of the 4 BMD sites that were measured in the study.
The research team created both a partially adjusted model for age, sex, and body mass index (BMI), as well as a fully adjusted model. It was noted that the fully adjusted model was additionally adjusted for hormone replacement therapy (HRT), osteoprotective therapy (OTX), and recent use of systemic glucocorticoid (GC).
Is There a Link Between Inflammatory Bowel Disease and Bone Mineral Density?
Researchers noted that compared with participants who did not have IBD, participants with IBD were more likely to be male, younger, and have a lower BMI.
Patients with IBD were also significantly more likely to be recent users of GCs (26% vs 6%).
At each of the 4 assessment sites—when adjusted for age, sex, and BMI—IBD was associated with lower T-scores. In addition, IBD was linked to having an osteoporotic T-score at L1-L4 and the total hip. However, when the model was further adjusted for exposure to GCs, HRT, and OTX, IBD was associated with only a marginal reduction in T-scores at both the total hip and the greater trochanter.
Furthermore, in the fully adjusted model, IBD was not directly linked to a higher risk of having an osteoporotic T-score at any of the 4 sites.
Although patients with IBD are at higher risk for low BMD and osteoporosis, this was not observed after adjusting for exposure to GCs and other medications.
These findings suggest that the harmful impact of inflammatory bowel disease on bone mineral density is predominantly related to GCs (rather than IBD itself). The researchers concluded that additional research is necessary to differentiate the independent effects of IBD, inflammatory activity, as well as its therapies on BMD and osteoporosis-related fracture risk.