An epidemiology study of fecal incontinence in adult Chinese women living in urban areas.

Fecal incontinence (FI) is the inability to control the discharge of intestinal contents including solid or liquid stool and gas. FI has been reported as a common disorder in Western societies, causing poor quality of life, depression, and social isolation. [ 1 ] However, only a small proportion of patients report the symptoms to their doctors because of embarrassment, resulting in the low probability of diagnosis and treatment. [ 2 ] Due to different definitions of FI and population samples, the prevalence of FI varies. Menees et al recruited 71,812 American individuals aged 18 years and older in 2015 and reported an FI prevalence of 14.4% (experienced FI in the past) and 5% (FI event within the past week). [ 3 ] We found a high prevalence of FI in some specific samples, such as old people in Japan (6.6%) and Taiwan, China or residents of Bali, Indonesia (22.4%). [ 4 – 6 ] Although some regional studies have been published, there is still no national population-based epidemiology research about the prevalence of and risk factors for FI in Chinese women. [ 7 ] The aims of this study were to identify the prevalence of and risk factors for FI in adult Chinese women living in urban areas.

This study was supported by the 12th Five-Year Plan National Project, which is funded by the Chinese National Health and Family Planning Commission for Disease Control and Prevention (No. 2014BAI05B00).

The study was conducted in accordance with the Declaration of Helsinki and was approved by the local Ethics Committee of Peking Union Medical College Hospital (PUMCH) approved this survey at May 15, 2013 (No. S-689). Informed written consent was obtained from all patients before their enrollment in this study. The data came from the national survey on the standardized diagnosis and treatment of pelvic floor disorders among adult Chinese women conducted by PUMCH in 2014 to 2015. This was a cross-sectional, face-to-face interview survey, conducted along with a national cervical cancer and breast cancer screening project which was free for all adult females. Six provinces (Liaoning, Gansu, Guangdong, Jiangsu, Shanxi, and Guizhou) were selected by computer-generated random number from the six geographic regions of the mainland of China (Northeast, North, East, South central, Northwest, and Southwest China) to reflect the diversity of economy and race of Chinese women. Three counties were selected from each province by a multicenter, stratified random sampling method according to urbanization and age distribution. A target sample size of 4500 urban living individuals for each province was selected in a stratified random sampling method by age according to the sixth national demographic investigations. Adult females who took part in the cancer screening project would be invited to finish the questionnaire under the direction of trained interviewers. To deal with the problem of population movement, only women who had lived in the current residence for more than 5 years were recruited. Pregnant and lactating women were excluded because the pelvic floor disorder would be worse in them. The ethics committee approved this survey, and each participant provided signed informed consent. Total 29,613 women living in urban China participated in this survey. And after excluding ineligible questionnaires, 28,196 women were enrolled in final analysis. The flowchart shows all the detailed information about this survey [Figure 1 ]. Figure 1 The flowchart of this study. ∗There are 215 questionnaires lacking information of two or more items. The flowchart of this study. ∗There are 215 questionnaires lacking information of two or more items. A standard questionnaire was administered by trained staff to obtain demographic characteristics including age, current marital status, height, weight, parity, residence, job, and race. We also collected information about the potential risk factors for FI, including history of surgery, chronic constipation (lasting more than 1 year), chronic cough (lasting more than 3 weeks), smoking, general medical diseases (including hypertension, diabetes mellitus, stroke, chronic bronchitis, cancer, and depression), and obstetric diseases (including inflammation, chronic pelvic pain, endometriosis, and uterine fibroids). Pelvic organ prolapse quantification (POP-Q) stages were measured by clinical doctors. If participants had both cesarean section (CS) and vaginal delivery history, they would be marked as vaginal delivery individuals and only those participants just had CS history would be marked as CS individuals. If participants had obstetric forceps/fetus aspiration history, they would also be marked as obstetric forceps/fetus aspiration individuals. The women who answered “yes” to the question “Do you have any experience of uncontrollable defection, or leakage of intestinal contents including gas, liquid, and solid stool, after feeling of bowel movement, but before going to the toilet?” were considered as FI patients. Jorge-Wexner score was used to estimate FI degree. [ 8 ] Patients can choose scores of 0 to 4 to represent the frequency of flatus, solid stool leakage, liquid stool leakage, using pads, and lifestyle alternations, including “never, occasional (less than once per month), sometimes (once per month–once per week), usually (once per week–once per day), or always (everyday),” respectively. IBM ® SPSS ® 21.0 statistical package (SPSS Inc., Chicago, IL, USA) and R Programming Language 3.5.1 were used in this research to deal with the data analysis. Measurement data were presentation as mean ± standard deviation. Demographic information and potential risk factors that have been reported in previous studies were analyzed by the Chi-square test. Cochran-Armitage test was used to investigate the trend of FI prevalence and the prevalence of flatus and solid and liquid stool leakage in the age groups. Multivariable logistic regression was used to estimate the adjusted odds ratios (OR) and 95% confidence intervals (CIs) of the potential risk factors. A two-sided P value ≤0.05 was considered to indicate statistical significance.

A total of 29,613 women living in urban areas participated in this survey; 28,196 (95.2%) women completed the questionnaire. The age distribution ranged from 20 to 99 years old, with a mean age of (44.6 ± 16.2) years. A total of 917 (3.3%) individuals were minorities. Table 1 shows the demographic characteristics of these urban participants. Characteristics of the 28,196 subjects interviewed. The unadjusted FI prevalence in adult Chinese women living in urban areas was 0.48% (95% CI: 0.41%–0.56%). After adjusting the weighting of each age-group according to the sixth national demographic investigations, the FI prevalence of urban Chinese women was 0.43% (95% CI: 0.35%–0.51%). The unadjusted FI prevalence in Gansu, Shanxi, Liaoning, Jiangsu, Guizhou, and Guangdong was 1.03%, 0.65%, 0.68%, 0.45%, 0.17%, 0.05%, and the adjusted FI prevalence was 0.86%, 0.55%, 0.75%, 0.36%, 0.18%, and 0.04%, respectively. Liquid stool leakage was the most common type of FI. Some participates reported more than one type of stool leakage experience. Figure 2 shows a clear age-related trend for overall FI prevalence and the incidence rate of solid stool, liquid stool and gas leakage ( P < 0.001). The mean Wexner score was 4.0 and 12% FI patients reported Wexner score ≥9. Figure 2 Trends of FI prevalence by age (years). The prevalence of overall FI, flatus, liquid stool, and solid stool leakage shows an obvious age-related increasing trend. P for trend <0.001. FI: Fecal incontinence. Trends of FI prevalence by age (years). The prevalence of overall FI, flatus, liquid stool, and solid stool leakage shows an obvious age-related increasing trend. P for trend <0.001. FI: Fecal incontinence. Risk factors associated with FI events were estimated by logistic regression analysis. Table 2   shows all potential risk factors accessed in the univariate analysis. Table 3   shows their adjusted OR, 95% CI and P value. Age, BMI ≥24 kg/m 2 , POP-Q stage, Chronic constipation, chronic cough, alcohol consumption, physical diseases including chronic bronchitis and cancer, gynecological diseases like gynecological inflammation increase the risk of FI ( P < 0.05). Univariate analysis of potential risk factors of urban participants ( N  = 28,196). Univariate analysis of potential risk factors of urban participants ( N  = 28,196). Multivariate analysis of the association between FI and potential risk factors. Multivariate analysis of the association between FI and potential risk factors. There were 23,004 females with labor history. Table 4 shows adjusted OR, 95% CI and P values of parity, delivery pattern, and fetal weight. The results have been adjusted by age. Vaginal delivery showed higher OR than CS. Multivariate analysis of the association between FI and obstetric factors ( N  = 23,004).

The adjusted FI prevalence for urban Chinese females was 0.43%, much lower than that in Western countries. Same as other studies, the most common FI symptom was liquid stool leakage. [ 9 – 11 ] Twelve percent of FI patients reported a Wexner Score of 9 or higher, which means restrained mobility. [ 12 ] There are some possible reasons for the low prevalence. First, since the interviewing sites were community hospitals, homebound patients were not involved in this research. And this could underestimate the FI prevalence. Second, considering the traditional conservative values, individuals who have experienced FI events may feel ashamed and difficult to talk with doctors and researchers about the embarrassing symptoms. [ 13 ] Third, FI is not a fatal disease and, thus, may not attract sufficient attention from females, especially those who experience FI at a very low frequency. Fourth, we hypothesize that race is also an influence factor. [ 14 ] Research carried out in Taiwan, China has reported a FI prevalence of 2.8% for adult women and 9.3% for women older than 65 years. This is much lower than that in Western countries. [ 14 ] In the analysis of the association between the FI incidence rate and age, a higher incidence can be found in the older age group, which is consisted with most FI epidemiology studies. [ 15 ] Some authors believe that the association between FI prevalence and age could have been confounded by a sphincter defect, pelvic floor disorders, poor health condition, and limited mobility. [ 16 ] Overweight and obese, chronic constipation, chronic cough, alcohol consumption, chronic bronchitis, cancer, depression, POP stage, and gynecological inflammation were entered into the logistic regression equation, what means that they are the independent risk factors for FI. In an epidemiology research about constipation and FI in the Netherlands, constipated responders were found to be more likely to suffer from FI than other patients. [ 17 ] An increase in the volume of stool stored in the rectum, a reduction in rectal sensation, incomplete evacuation, and the laxative usage can be the possible mechanisms for the co-occurrence of FI and constipation. [ 13 , 14 , 18 – 20 ] Similar to the studies about urinary incontinence, chronic bronchitis, and chronic cough can cause frequent outbursts of high abdominal pressure, which might lead to exhausted pelvic floor muscles and other related mechanisms. [ 21 – 24 ] Radiotherapy, poor health, and nerve damage in cancer patients increased the possibility of FI. [ 25 , 26 ] We should also pay attention to the drugs associated with these physical diseases, such as calcium channel antagonists/broad spectrum antibiotics/metformin/tricyclic anti-depressants, as these compounds can change sphincter tone and/or cause constipation, diarrhea, or reduced alertness. [ 27 ] Consistent with the research on diet and eating patterns of FI individuals, alcohol is an independent risk factor, which suggests that doctors need to provide abstinence education to the FI individuals. [ 28 ] POP is a common gynecological disorder that leads to many annoying symptoms, such as urinary incontinence and obstacles to intercourse, and a multidisciplinary approach is recommended for POP and incontinence. [ 29 – 31 ] We found a high correlation between II/III-IV POP stage and FI, which suggests an active attitude to dealing with POP symptoms for the gynecologists if the patients complain of FI symptoms. In addition, this research found that BMI ≥24 kg/m 2 was a risk factor for FI event. Weight loss was strongly suggested, which was also an important method to control POP symptom. [ 29 ] There is few specific research reporting the association between FI and gynecological issues. We estimate chronic pelvic pain, gynecological inflammation, endometriosis, and uterine fibroids’ role in FI occurrence, and gynecological inflammation was the risk factor for urban women. The mechanisms need more investigations. The association between labor history, obstetric factors, and FI was controversial. Though some hypotheses suggested that pregnancy and delivery could cause injury to pelvic tissue, a large number of studies have not reported this specific association. [ 32 , 33 ] Kepenekci et al reported FI by 1.1% in population with cesarean only, 2.9% in women with vaginal delivery, and 3.6% in women with mixed type but the difference disappear after adjusting by ages. [ 15 ] The labor history is not a risk factor for FI in our study. However, in the subgroup analysis of females with labor history, vaginal delivery increased OR compared with female with CS delivery and once or twice deliveries. This is the largest national population-based epidemiological survey about FI prevalence and risk factors in adult Chinese women living in urban areas. Plenty of potential risk factors including basic demographic information, general medical diseases, gynecology diseases, and obstetric factors were analyzed in this research. Another strength is that we invited clinical doctors to check the POP-Q stage of the interviewees and that the POP-Q stage has been shown to be a great risk factor for FI. The research also has some limitations. Data were collected by self-reporting according to the questionnaires instead of clinical examinations. All participants came from the outpatients of community hospital which may omit some FI patients who were confined to bed. In conclusion, this was a national population-based epidemiological research about the prevalence of and risk factors for FI in adult women living in urban areas of China. We found a lower prevalence of FI in our cohort compared with that reported in other countries and places. However, with the second-child policy and the demographic change in China, FI could become a more common symptom. Therefore, gynecologists should pay more attention to women who have POP, chronic constipation, chronic cough, and physical diseases and those who consume alcohol.

None.