What longitudinal studies exist on anorectal function after years of frequent receptive anal intercourse?
Executive summary
There are surprisingly few true longitudinal studies that track anorectal structure and function over years of frequent receptive anal intercourse (RAI); the literature is dominated by cross‑sectional surveys, small physiologic case‑control studies, and narrative reviews that describe associations but not causation [1] [2] [3]. Small clinical physiology studies report lower resting anal pressures, reduced mucosal sensitivity, and higher symptom reporting among people who practice receptive anal intercourse, but these data derive from short‑term or cross‑sectional designs rather than prospective cohorts that follow subjects over years [4] [5] [6].
1. What the published physiological studies show (but don’t prove longitudinal change)
Early clinical investigations measuring anorectal manometry and sensation compared groups of anoreceptive men with controls and reported significantly lower maximum resting anal pressure, reduced anal mucosal electrosensitivity, and higher rates of reported anal incontinence in the receptive group—findings repeated in small samples from the 1990s and reproduced in later physiology reports—but these were cross‑sectional comparisons, not follow‑up studies documenting progressive change over time [4] [5] [7]. Those physiologic tests (manometry, endoanal ultrasound, electrosensitivity) remain the recommended combination to evaluate structure and function, underscoring that existing data describe differences in snapshots rather than trajectories [1] [6].
2. Large surveys and population data: prevalence signals without temporality
Large-scale survey work has quantified prevalence and associations: a multi‑thousand‑subject survey of men who have sex with men found fecal incontinence and other anorectal complaints reported among RAI practitioners, and national survey analyses (NHANES) have probed links between anal intercourse history and fecal incontinence across population samples [1] [2] [6]. These studies provide statistical associations and risk estimates across broad samples but are cross‑sectional or retrospective in nature; they cannot confirm whether RAI leads to progressive anorectal dysfunction over years because they lack pre‑exposure baselines and repeated objective measures [1] [2].
3. Recent work, instrument development, and the measurement gap
Contemporary scholarship is beginning to address the measurement problem: new instruments such as the Anorectal Sexual Function Index are being developed and validated to capture the lived experience and clinical domains relevant to RAI, which could enable future longitudinal research if applied prospectively [8]. Recent online surveys and mixed‑methods studies (2022–2024) document relationships between lifetime RAI exposure and pelvic sensations, chronic pelvic pain syndromes, and self‑reported anorectal symptoms, but they are again cross‑sectional and emphasize the need for standardized, repeatable outcome measures to build longitudinal evidence [9] [10] [11].
4. Reviews, heterogeneity, and dissenting findings
Narrative reviews and systematic summaries repeatedly note heterogeneity in study design, small sample sizes, and inconsistent outcomes—some studies report lower squeeze pressure or altered pressure profiles in RAI practitioners, while others find no consistent link to fecal incontinence or progressive dysfunction—leading reviewers to caution that causal inference is premature [1] [2] [3]. Reviews also highlight multiple potential mechanisms (stool consistency, rectal compliance, pelvic floor dysfunction, sensory changes) and recommend combined structural and functional testing when symptoms occur, implicitly signaling that the evidence base cannot yet answer longitudinal causation [6] [3].
5. Bottom line: what longitudinal evidence exists and what’s needed
There are essentially no robust, long‑duration prospective cohort studies that repeatedly measured anorectal structure and function in people before and after years of frequent RAI; existing longitudinal claims are absent from the reviewed literature, which is dominated by cross‑sectional physiologic studies, large surveys, and narrative reviews [1] [2] [4] [6] [3]. To establish whether frequent RAI causes progressive anorectal dysfunction will require prospective cohorts using standardized tools (manometry, endoanal ultrasound, validated symptom indexes like the ASFI) with adequate sample sizes, confounder control, and long follow‑up—an agenda explicitly recommended across recent sources [1] [8] [6].