Smoking, asthma tied to worse faecal incontinence symptoms

More severe faecal incontinence symptoms appear to burden tobacco smokers, reveals a recent study presented at DDW 2023. Tobacco use is also associated with weaker anal sphincter tone and increased rectal hypersensitivity on high-resolution anorectal manometry (HRAM).

“Smoking cessation may represent a strategy for management of faecal incontinence, although further studies are needed to assess the underlying mechanism and reversibility of effect,” said the researchers, noting that tobacco use has been associated with smooth muscle dysfunction in the gastrointestinal (GI) tract, such as reduced lower esophageal sphincter tone.

Consecutive adults referred for HRAM at a tertiary centre from 2019 to 2022 were included in this study. Then, the researchers prospectively collected surveys at time of HRAM, including lower GI domains (ie, diarrhoea, incontinence, constipation) of GI-PROMIS*, global symptom severity (GSS) for global hindgut symptoms on a 100-mm visual analogue scale, 12-item Short-Form Health Survey (SF-12) for health-related quality of life, and smoking history.

Finally, Chi-squared or student t-test or Spearman correlation (univariate) and general linear regression (multivariate) were used to carry out statistical analyses.

Of the 385 patients (mean age 53.4 years, 81 percent female, body mass index [BMI] 27.0 kg/m²) enrolled in the study, 112 (29.1 percent) endorsed tobacco use. Smokers were more likely to be older (58.5 vs 51.3 years; p=0.0002) and have higher BMI (28.0 vs 26.6 kg/m²; p=0.054) than nonusers. [DDW 2023, abstract 1670]

Additionally, smokers had lower GI-PROMIS incontinence score (5.61 vs 5.29; p=0.032) and mental component score on SF-12 (42.6 vs 46.7; p=0.028). No significant associations were observed with other symptom instruments.

On HRAM, tobacco users had lower anal sphincter resting pressure than nonusers (52.6 vs 65.9; p<0.001), and this association was sustained on multivariate analysis (β, ‒8.57; p=0.018) after adjusting for age, gender, obesity, thyroid dysfunction, irritable bowel syndrome, diabetes, and vaginal delivery.

Notably, univariate and multivariate analyses revealed a higher incidence of rectal hypersensitivity among smokers (univariate: 71.4 percent vs 60.8 percent; p=0.049; multivariate: odds ratio, 2.35, 95 percent confidence interval, 1.20‒4.62; p=0.013).

On London classification, smokers also had a higher incidence of anal hypotension with or without hypocontractility (34.9 percent vs 23.1 percent; p=0.018).

Asthma, COPD

In another study presented at DDW 2023, women with obstructive lung diseases were found to be at higher risk (17 percent increased risk with asthma; 16 percent with chronic obstructive pulmonary disease [COPD]; 29 percent with both asthma and COPD) of faecal incontinence, with concurrent obstructive processes augmenting such effect. [DDW 2023, abstract 1678]

“These findings suggest that asthma and COPD patients may represent a population that could be targeted for faecal incontinence screening and mitigation efforts,” the investigators said. “Further studies are needed to determine potential mechanisms by which obstructive diseases impact continence and whether disease control might attenuate the risk of subsequent faecal incontinence.”

Women in the Nurses’ Health Study were included in this analysis. The investigators initially collected data on faecal incontinence in 2008. Incident faecal incontinence was defined as at least monthly solid or liquid incontinence in the past year on the 2010 or 2012 questionnaires without prevalent faecal incontinence in 2008, when the question was first asked.

COPD was defined as reported physician diagnosis or reported physician diagnosis plus a diagnostic test, while asthma was defined as reported physician diagnosis or reported physician diagnosis plus medication use.

*Gastrointestinal Patient Reported Outcomes Measurement Information System