Is There Any Association Between Fat Body Mass and Bone Mineral Density in Patients with Crohn's Disease and Ulcerative Colitis?

Background

The study aimed to investigate the association between fat body mass and bone mineral density (BMD) of the lumbar spine (L1-L4), femoral neck, and total body.

Methods

We studied 95 patients with Crohn's disease (CD), 68 with ulcerative colitis (UC), and 40 healthy adults (control group-CG) aged 18-50 years old. The BMD of lumbar spine and femoral neck was assessed as well as body composition.

Results

A lower fat mass percentage was observed in about 8% of CD, 13% of UC, and 3% of CG. An increased percentage of fat mass was common, and occurred above 50% of CD, 40% of UC, and about 60% of CG. Body fat mass and fat mass percentage were significantly lower among UC compared with the CG (p-value < 0.001) and CD (p-value < 0.01) in women. Body fat mass correlated positively with the BMD and T-score of L1-L4 and total body mass in men with UC. We found a positive correlation between the fat body mass and BMD and T-score of L1-L4, femoral neck, and total body in women with IBD. Among CG, positive correlations occurred between the fat body mass and BMD of L1-L4, BMD of total body, and T-score of total body, but only in men. CRP (C-reactive protein) correlated negatively with fat body mass only in men with CD.

Conclusions

A higher fat mass percentage is common among IBD patients and healthy adults despite a normal body mass index. Body fat mass is a predictor of nutritional status and likely influences the course of the disease, as it correlated positively with BMD, T-score, and Z-score. The association between fat tissue and bone health appears to be stronger in women. Further studies are needed to investigate additional factors that may affect bone health in IBD.