Risk factors for female anal incontinence: new insight through the Evanston-Northwestern twin sisters study.
OBJECTIVE
To evaluate risk factors for anal incontinence using an identical twin sisters study design to provide control over genetic variance.


METHODS
A total of 271 identical twin sister pairs (mean age 47 years) completed the validated Colorectal Anal Distress Inventory questionnaire detailing the presence and severity of anal incontinence. Data were analyzed using a stepwise logistic regression with repeated binary measures to account for correlated data within twin pairs. Three different statistical models were used to analyze nonobstetric as well as obstetric risk factors separately.


RESULTS
Significant risk factors for anal incontinence and higher Colorectal Anal Distress Inventory anal incontinence subscale scores included age 40 years or older (fecal: odds ratio [OR] 2.82, 95% confidence interval [CI] 1.21-6.0; flatal: OR 1.90, 95% CI 1.11-3.24), menopause (fecal: OR 2.10, 95% CI 1.15-3.8; flatal: OR 2.11, 95% CI 1.43-3.13), increasing parity (parity > or = 2; fecal: OR 3.09, 95% CI 1.25-7.65; flatal: OR 2.72, 95% CI 1.65-4.51), and the presence of stress urinary incontinence (fecal: OR 2.11, 95% CI 1.12-3.98; flatal: OR 1.72, 95% CI 1.14-2.59). Obesity was associated with significantly higher Colorectal Anal Distress Inventory anal incontinence subscale scores (mean difference 5.18, P = .007). Cesarean delivery after initiation of labor was associated with a lower prevalence of anal incontinence than vaginal birth; however, this difference was not statistically significant (17% compared with 4%, P = .11). No anal incontinence was noted in women who had only elective cesarean deliveries.


CONCLUSIONS
Age, menopause, obesity, parity, and stress urinary incontinence are the major risk factors for female anal incontinence.
Abramov
Yoram
Y
Division of Urogynecology and Reconstructive Pelvic Surgery, Evanston Continence Center, Northwestern University, Feinberg School of Medicine, Evanston, Illinois, USA. y-abramov@northwestern.edu
Sand
Peter K
PK
Botros
Sylvia M
SM
Gandhi
Sanjay
S
Miller
Jay-James R
JJ
Nickolov
Angel
A
Goldberg
Roger P
RP
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016022:Case-Control Studies; D036861:Delivery, Obstetric / Q000009:adverse effects; D005242:Fecal Incontinence / Q000209:etiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D014430:Twins, Monozygotic