Influence of Gender and Age on Anorectal Function: Normal Values from Anorectal Manometry in a Large Caucasian Population

Abstract

Introduction: In the literature, data on the effects of gender and age on the pressure data of anorectal manometry differ. Possible reasons are investigation of only small numbers of healthy people and comparison of only 2 groups with large age differences. In addition, data about the influence of gender or age on anorectal sensation are sparse. Therefore, the aim of the present study was to determine the influence of gender and age on anorectal manometry in a large healthy female and male cohort spanning a great age range. Methods: Anorectal manometry was performed in 72 women and 74 men with a median age of 64 years in both groups (ranges: women 22–90 years; men 23–88 years). We determined mean anal resting and squeeze pressure as well as minimal rectal balloon volume for perception and for urge/desire to defecate. The Mann-Whitney U test was used to analyze for gender differences, regression analysis to search for age influences. Results: Squeeze pressure (p = 0.007) and perception threshold (p < 0.001) are significantly lower in females, while the mean resting pressure and urge threshold are similar in females and males. Mean resting pressure (women p < 0.0001; men p = 0.03) and mean squeeze pressure decrease (women p < 0.0001; men p = 0.004) with age. An age-related increase in sensory thresholds (= decreased rectal sensitivity) is only seen in females (perception threshold p = 0.01; urge threshold p = 0.04). Conclusion: Most of the parameters measured by anorectal manometry (anal canal pressure, sensory thresholds) are influenced by gender and age. Therefore, the results of anorectal manometry must be interpreted in relation to sex- and age-adapted normal values.

Risk factors for internal anal sphincter dysfunction in Japanese adults

“…The IAS plays a key role in maintaining continence, providing 55% -85% of MRP [3,4]. Several studies have investigated the effect of sex on resting pressure of the anal canal [12][13][14][15]. The data are contradictory, with about half of the studies reporting comparable resting pressures in women and men, and the other half citing lower resting pressure in women.…”

“…Some studies observed a significant lowering of MRP with age (more often in women than in men), while others found only a small decrease in MRP that did not reach statistical significance. Other studies did not see a decreased MRP in their older subjects [12][13][14][15]. In addition to the aforementioned problem of small sample size, most studies included patients of varying ages and grouped them differently.…”

An International Urogynecological Association (IUGA)/International Continence Society (ICS) joint report on the terminology for female anorectal dysfunction

“…Manometry assesses the mechanical strength of the anal sphincters (76,77). A range of methods are available, including water perfused, solid state and microballoon systems.…”

Accuracy of Anorectal Manometry in Patients with Fecal Incontinence

“…However, age and gender have to be considered when comparing healthy and incontinent people. Mean resting (MRP) and squeeze (MSP) pressure decreases with aging [5]. Furthermore, female sex influences anorectal pressure as well as sensory parameters [5].…”