Morphometric measurement of submucosal thickness in areas of fat deposition in the terminal ileum and colonic sections, with correlation with body mass index, weight and age: A male autopsy study

Aims: An increased amount of submucosal (SM) fat in the colon on imaging is considered to be characteristic of inflammatory bowel disease (IBD); however, a recent study in patients without IBD reported a correlation between colonic SM fat deposition and body weight (BW). The aim of this study was to perform a morphometric investigation of SM thickness in areas of fat deposition in the terminal ileum (TI), ileocaecal valve (ICV), and colonic sections, to determine whether there are variations by site, and whether it shows a correlation with BW, body mass index (BMI), or age. Methods and results: Representative samples of TI, ICV and colonic sections were collected prospectively from 115 autopsy cases without IBD. All of the study subjects were male (Veterans Hospital). SM thickness was measured in areas of fat deposition. Correlation analysis was performed between SM thickness and BW, BMI, and age. Fat deposition was common; however, with the exception of the ICV, it was neither consistent nor prominent, and it did not show a statistical correlation with BW, BMI, or age. Conclusions: SM fat deposition is common but not uniform or conspicuous in the TI or colon. In contrast to extravisceral intra-abdominal fat, it does not show a correlation with BW or BMI, and is not associated with ageing. As all study subjects were male, gender-dependent variability cannot be excluded.