Purpose: Anorectal manometry provides objective information about anorectal function, but its results depend on the examiner's skill, the type of equipment, and subject characteristics like age or gender. This single institution, prospective study was performed to investigate the effect of gender and age on the results of anorectal manometry.
Methods: All included subjects completed a questionnaire to assess their bowel function. The survey included 13 validated questions (eight on constipation and five on incontinence) and was used to exclude subjects with pathological constipation or incontinence. Subjects with normal bowel function underwent anorectal manometry to measure anal sphincter length (ASL), maximum resting pressure (MRP), and maximum squeeze pressure (MSP), and the results were compared by gender and age.
Results: The mean age of the 154 participants (94 male and 60 female) was 59.1 years. ASL was greater in men (4.23 vs. 3.85 cm, p < 0.001). MRP was not significantly different according to gender (p = 0.93), but MSP was higher in men (190.18 vs. 116.49 mmHg, p < 0.001). ASL did not correlate with age (p = 0.707). MRP was inversely related to age in both men (R (2) = 0.152, p < 0.001) and women (R (2) = 0.282, p < 0.001), and MSP only in women (R (2) = 0.210, p < 0.001).
Conclusions: Anorectal manometric parameters are influenced by gender and age. This should be taken into consideration when interpreting manometric readings in a clinical setting.