Colorectal dimensions in the general population: impact of age and gender

Constipation is among the most common gastrointestinal disorders, although, there is no generally accepted objective diagnostic criteria thereof. It has been proposed that colorectal dimensions assessed with Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) may support the diagnosis, but normative data are lacking. The aim of this study was to describe colorectal dimensions in a sample of the general population and to investigate whether the dimensions were under influence by age and gender.

The maximum diameters and cross-sectional areas of the ascending colon, descending colon and rectum were determined from 119 CT scans of trauma patients (age groups from 15 to 70 years, 84 men and 35 women). A regression model was applied to explore the impact of age and gender on colorectal dimensions.

Overall, great variations were found for all colorectal diameters and cross-sectional areas (median diameter (5% percentiles; 95% percentiles): ascending 46 (26; 63) mm; descending 29 (16; 48) mm; rectum 39 (22; 67) mm. Women had larger rectal cross-sectional areas, reflecting more rectal content, compared to men (p = 0.003). Age did not affect colorectal diameters or cross-sectional areas (all p > 0.10).

Great variations of colorectal dimensions were found. Larger rectal cross-sectional areas in women could likely reflect the fact that women have increased prevalence of constipation. Future studies should take gender into consideration when evaluating colorectal dimensions.