P536 Is there any association between fat body mass and bone mineral density in patients with Inflammatory Bowel Disease?
Ratajczak, A.E.(1)*;Michalak, M.(2);Szymczak-Tomczak, A.(1);Rychter, A.M.(1);Zawada, A.(1);Skoracka, K.(1);Dobrowolska, A.(1);Krela-Kaźmierczak, I.(1);
(1)Poznan University of Medical Sciences, Department of Gastroenterology- Dietetics and Internal Diseases, Poznan, Poland;(2)Poznan University of Medical Sciences, Department of Computer Science and Statistics, Poznan, Poland;
Low bone mineral density (BMD) in inflammatory bowel disease (IBD) is multifactorial and includes nutritional status. The study aimed to look for the association between fat body mass and fat-free mass and BMD of the lumbar spine (L1-L4), femoral neck and total body.
The study subjects included 95 patients with Crohn’s disease (CD), 68 with ulcerative colitis (UC) and 40 healthy adults (control group - CG) in age of 18-50 years old, recruited at the Department of Gastroenterology, Dietetics and Internal Medicine, Poznan University of Medical Sciences between 2020-2021. The summary of the methods is presented in Figure 1.
DXA- Dual-energy X-ray absorptiometry
A lowered fat mass percentage occurred in about 8% of CD, 13% of UC and 3% of CG. Additionally, an increased percentage of fat mass occurred above 50% of CD, 40% of UC and about 60% of CG. It is interesting because the median, lower and upper quartile for BMI (body mass index) was normal for CD [21.70 (19.20; 24.40] and UC [20.30 (18.45; 24.05)]. Fat body mass and fat mass percentage were significantly lower among UC compared with the CG and CD in women but not men. Additionally, healthy women presented higher fat-free mass than CD and UC women. We did not find the same differences for men. In CD women, but not men, with a high body fat percentage, we find a higher BMD and T-score of L1-L4-but than the standard body fat percentage. Fat body mass correlated positively with BMD and T-score of L1-L4 and total body in men with UC but not in men with CD and women with UC. However, we find a positive correlation between fat body mass and BMD and T-score of L1-L4, femoral neck and total body. 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. Fat-free mass correlated positively with BMD and T-score of L1-L4 and total body and BMD, T-score and Z-score of the femoral neck in CD women but not UC women. In men, correlations occurred between the fat-free mass and BMD and T-score of L1-L4, femoral neck and total body in CD. Among UC, fat-free mass correlated with BMD, T-score, and Z-score of L1-L4, femoral neck and total body. We did not find a correlation in CG. CRP (C-reactive protein) correlated negatively with fat body mass only in men with CD and negatively in healthy women.
A higher fat mass percentage is common among IBD patients and healthy adults despite normal BMI. Probably, fat body mass and fat-free mass are predictors of nutritional status and the course of the disease, therefore correlated positively with BMD, T-score and Z-score. On the other hand, a high-fat mass percentage with a normal BMI indicates metabolic obesity with normal weight.