Effects of age on anal function in normal women

Purpose: To study effects of age on anal function in healthy women. Methods: A study of 75 women with no known anorectal disease, aged 20 to 83 (mean 50) years, mean parity 2 (range 0-4). Perineal position at rest (PR), descent during straining (PS), maximum resting pressure (MRP) maximum squeeze pressure (MSP) of the anal sphincters, and pudendal nerve terminal motor latency (PNTML) were measured. Data were analysed using the multiple regression technique including age and parity in the model. Results: Increasing age was significantly associated with a weakening of anal function. PR and PS were both lowered (P < 0.0001 and P = 0.0001). Anal sphincter pressures were reduced (MRP: P = 0.004, MSP: P = 0.015), and age was associated with an increased mean PNTML (P < 0.0001). All associations seemed to be linear. Parity was associated with a lowering of both PR and PS but not with the other parameters. Age accounted for 13-34% of the total variability seen in the tests of pelvic floor function. Conclusion: Age leads to a consistent reduction in anal function and this is likely to increase the risk of faecal incontinence in old age. From the current data we suggest that in normal women with an uncomplicated obstetric history increasing age is associated with significant changes in anal function whereas long-term effects of vaginal deliveries play a minor role. Moreover our results suggest gradual changes throughout adult life, rather than large changes occurring after menopause.