How common is fecal incontinence after long-term anal sex?

1. What the big surveys actually measured — and their limits

The largest study available surveyed 21,762 MSM via an online convenience sample and asked about involuntary stool leakage in the last month; it found significantly higher FI prevalence among men reporting frequent RAI and identified related risk factors such as chemsex and fisting ^{[1] [5]}. But authors and summaries emphasize key limitations: non‑random recruitment, self‑reporting, and FI assessed only for one recent time window (past month), so the studies show associations at a point in time rather than proven long‑term causation ^{[4] [6]}.

2. What nationally representative data show

Analyses of NHANES 2009–2010 data (6,150 adults, age 20–69) reported that adults who had ever engaged in anal intercourse had higher rates of FI; adjusted models showed especially increased odds among men ^{[2] [3]}. That analysis defined FI as monthly leakage of liquid, solid, or mucus and used standardized questionnaires, lending population‑level weight to the association, though it too is cross‑sectional ^{[2] [3]}.

3. How common is “fecal incontinence” in these studies?

Reported prevalences vary by sample and definition: the large MSM online study reported 12.7% FI prevalence among men with very frequent RAI vs. 5.7% among men not engaging in RAI ^[1]. NHANES reported overall FI in the studied samples of roughly 4–8% depending on subgroup and definitions, with higher rates among those reporting anal intercourse ^{[3] [7]}.

4. Risk factors beyond frequency of anal sex

Both the MSM survey and narrative reviews highlight additional correlated behaviors that track with higher FI rates: chemsex (substance use during sex), fisting or hard BDSM practices, and lower socioeconomic status were associated with greater FI prevalence ^{[1] [5]}. A 2024 narrative review concluded anal penetrative intercourse can be a risk factor for anorectal dysfunctions including FI in both men and women, citing multiple studies ^[8].

5. Biological plausibility and clinical signals

Small clinical series and manometry data suggest decreased anal sphincter pressures have been observed in some people who practice anal intercourse, providing a plausible mechanism for loss of continence in some cases ^[3]. Narrative reviews synthesize these findings to say that repetitive anal stretching could contribute to anorectal dysfunction, though robust longitudinal mechanistic studies are limited ^{[8] [3]}.

6. What these studies do not establish

Available sources do not provide long‑term, prospective incidence data proving that “long‑term anal sex” causes FI in most practitioners; rather, they document higher prevalence and associations in cross‑sectional and self‑reported cohorts ^{[4] [6]}. Causal direction, role of confounders (e.g., substance use, trauma, obstetric history in women), and absolute lifetime risk remain not well defined in the cited reporting ^{[4] [9]}.

7. Practical takeaways and competing perspectives

Public‑facing guidance emphasizes risk mitigation: gradual preparation, lubrication, pelvic floor care, and avoiding high‑risk practices may reduce injury—views echoed in harm‑reduction content though such advice is based on practice principles rather than randomized trials ^[10]. Medical reviewers and primary studies advise clinicians to assess sexual practices when evaluating FI because the behavior is a plausible contributing factor, especially in men ^{[2] [3]}. Some outlets report the association more alarmingly, while clinical summaries and reviews frame it as one of several risk factors to weigh ^{[7] [8]}.

8. Bottom line for readers

Large surveys and reviews consistently find an association between anal penetrative sex and higher rates of fecal incontinence, with stronger signals in men and in those reporting frequent or high‑intensity practices like fisting or chemsex ^{[1] [2] [8]}. These data are largely cross‑sectional and self‑reported, so they establish correlation and biological plausibility but do not quantify precise lifetime risk for an individual; prospective, controlled long‑term studies are not reported in the sources cited here ^{[4] [6]}.