Tobacco Use is Associated with Anorectal Sensorimotor Dysfunction and Greater Fecal Incontinence Severity

Background: Tobacco use has been associated with a range of digestive symptoms and gastrointestinal smooth muscle dysfunction. However, the impact of tobacco use on fecal incontinence (FI) and anorectal function remains unclear. We aimed to evaluate whether tobacco use disrupts anorectal sensorimotor function and affects FI severity Methods: Consecutive patients referred for high-resolution anorectal manometry (HRAM) at a tertiary center were included. Validated survey instruments (GI-PROMIS, 12-item short-form health survey [SF-12], global symptom severity) and smoking status were prospectively collected at time of testing. HRAM metrics and London classification diagnoses were compared according to tobacco exposure. Multivariable analyses adjusting for potential confounders were performed. Results: Among 385 patients (81% female; mean age 53.4) enrolled, 112 (29.1%) reported tobacco use. Compared to non-smokers, tobacco users had greater FI severity on GI-PROMIS (6.06±0.28 vs. 5.29±0.17, p=0.017), worse mental component score on SF-12 (42.6±1.5 vs 46.7±1.0, p=0.028), lower anal sphincter resting pressure (52.6±2.4 vs 65.9±1.8 mmHg, p<0.0001), more rectal hypersensitivity (71.4% vs. 60.8%, p=0.049), and higher prevalence of anal hypotension ± hypocontractility per London classification (34.9% vs. 23.1%, p=0.018). On multivariable general linear regression, tobacco use independently correlated with worse FI symptoms (β=1.28, p=0.035) and lower anal resting pressure (β=-8.57, p=0.018). Tobacco use also remained a significant predictor for rectal hypersensitivity on logistic regression (OR 2.35, 95% CI:1.20-4.62, p=0.013). Conclusions: Tobacco use is independently associated with more severe FI symptoms, weaker anal sphincter tone, and increased rectal hypersensitivity . Further studies should assess reversibility of the observed anorectal sensorimotor dysfunction with tobacco cessation.