Int Urogynecol J (2010) 21:589–593 DOI 10.1007/s00192-009-1041-4
ORIGINAL ARTICLE
Epidemiological study of urge urinary incontinence and risk factors in China Lan Zhu & Jinghe Lang & Chunyan Liu & Tao Xu & Xiaochun Liu & Lin Li & Felix Wong
Received: 18 May 2009 / Accepted: 27 October 2009 / Published online: 24 February 2010 # The International Urogynecological Association 2010
Abstract Introduction and hypothesis To evaluate the prevalence and risk factors of urge urinary incontinence (UUI) in Chinese adult women. Methods A cross-sectional study using the multistaged random sampling method. Twenty thousand Chinese women aged ≥20 years were interviewed. Results Of the women aged 20–99 years, the prevalence of UUI was 2.6%, which increased with age. Age, waist circumstance, constipation, chronic pelvic pain, history of gynecological diseases, and menopausal status were independent risk factors of UUI. Women aged 60 or above were 2.329 times more likely to suffer UUI as compared to women aged 20–40. Women in perimenopausal or postmenopausal status were, respectively, 1.766 or 2.285 times more likely to suffer UUI as compared to women in normal menstruation. However, parity and mode of delivery were not risk factors. Conclusions The prevalence of UUI is 2.6% among Chinese adult women. Age is a major independent risk factor of UUI.
L. Zhu (*) : J. Lang (*) : C. Liu : X. Liu : L. Li Department of O/G, Peking Union Medical College Hospital, Beijing 100730, People’s Republic of China e-mail:
[email protected] T. Xu Department of Epidemiology, Peking Union Medical College, Beijing 100730, People’s Republic of China F. Wong Department of O/G, Liverpool Hospital, University of New South Wales, Sydney 2170, Australia
Keywords China . Epidemiology . Urge urinary incontinence . Women
Introduction Urinary incontinence (UI) remains a worldwide problem affecting adult women across different cultures and races. As defined by the International Continence Society (ICS), UI is the complaint of any involuntary leakage of urine [1]. Urge urinary incontinence (UUI) is a subtype of UI. UUI is the complaint of involuntary leakage accompanied by or immediately preceded by urgency [1]. From 13 studies of female UI in the general population that covered an age span of at least 30 years, it showed that the median level of prevalence estimates gave a picture of increasing prevalence during young adult life (prevalence 20–30%), a broad peak around middle age (prevalence 30–40%), and then a steady increase in the elderly (prevalence 30–50%) [2]. The reported prevalence of UUI varies widely, ranging from 0.4% to 11% according to different epidemiological reports [3, 4]. This variation is mainly due to differences in definitions, target populations, questionnaire design, and selection criteria [5]. Obtaining information about the epidemiology of UUI in Chinese adult women may help guide treatment strategies and provide preventive measures. Therefore, our main objectives were to investigate the nationwide prevalence, subtypes, and associated risk factors of UUI in Chinese adult women by using the modified Bristol female lower urinary tract symptoms (BFLUTS) questionnaires, and to evaluate the epidemiology of UUI in Chinese adult women. The long-term goal was to provide evidence for the establishment of medical preventive strategies and treatment for UUI in China in future.
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Methods
Int Urogynecol J (2010) 21:589–593
questionnaires were error checked before double-entry computer input.
Study design and participants This was a cross-sectional survey using multistaged random sampling across China. Geographically, six areas were included: northwest China, southwest China, north China, East China, Northeast China, and South China. In every prefectural region, we sampled one province, and one welloff city and one undeveloped city were randomly selected in every sampled province with the simple random sampling method. The sampled cities were urban Lanzhou and rural Gaoba (northwest); urban Chengdu and rural Xipu (southwest); urban Taiyuan and rural Yushu (north China); urban Wuxi and rural Renci (east China); urban Dalian and rural Shahe (northeast); and urban Foushan and rural Danzao (south China). These 12 places (six urban and six rural communities) are moderate in economic development, environment, lifestyle, and people's life expectancy. Our target population consisted of all eligible residents aged 20 years or older in updated 2006 census lists from community registry offices, and people living in the registered areas for at least 10 years. In every city, we obtained the demographic data of women aged 20–99 years with the help of local maternity and child care hospitals and neighborhood committees. According to the predetermined sample size, two or three communities were selected with cluster sampling method in every place. All eligible women were considered as the survey subjects. About 1,000 subjects were surveyed in each city. Furthermore, the subjects' data from the pilot study in Beijing were also incorporated into the present study. Finally, 20,000 subjects who attended the local hospital or community meeting also entered in the study voluntarily after we explained to them about the significance of the survey and the questionnaire. All eligible participants signed the agreement form. Diagnostic criteria Definitions in the study are consistent with the standards recommended by the ICS [1] except where specifically noted. UUI is the complaint of involuntary leakage accompanied by or immediately preceded by urgency. Measures The questionnaire was adapted from the authorized BFLUTS and included the following additional information: general health status and sociodemographic background of participants. The questionnaire was designed and administered under the guidance of epidemiologists, and filled out by trained health-care personnel themselves, most of whom were obstetrics and gynecology doctors. The
Statistical analysis Univariate logistic regression model was performed to compare the prevalence of different groups. Variables that had P values less than 0.10 in univariate analysis entered the multivariate regression model. Multivariate logistic regression model was conducted to analyze potential risk factors of UUI. Risk factors were assessed with odds ratios and 95% confidence intervals. EpiData 3.02 and SPSS 12.0 were used as the data management software and statistical analysis software, respectively. A two-sided test and 0.05 significance level were used to infer the statistically significant difference.
Results The total sample size was 20,000 women from Beijing City and seven provinces (Gansu, Sichuan, Shanxi, Jiangsu, Liaoning, and Guangdong). After exclusion of 976 invalid questionnaires, the final sample for analysis was 19,024. The doctors who had been trained collected the questionnaires with the patients face to face. The patients included some old women who were willing to fit this survey, so the response rate was high. The age distribution ranged from 20 to 99 (45±16) years, and most women had given birth more than once (16,771 women). Among them, 2,539 women had given birth by cesarean section (2,404 only once and 55 twice or above). The overall prevalence of UI was 30.9%, and the prevalence of UUI was 2.6%. Risk factors of UUI according to logistic regression analysis are shown in Table 1. In the univariate analysis model, age, parity and mode of delivery, waist circumstance, constipation, chronic pelvic pain, history of gynecological diseases, and menopausal status were associated with prevalence rate of UUI. The prevalence of UUI increased with age. Women with UUI were more likely to be older and were associated with vaginal delivery, perimenopausal, and postmenopausal status. Women who had suffered from constipation, gynecological diseases, and chronic pelvic pain (CPP) were more likely to be attacked by UUI. Larger waist circumstance was also a significant risk factor. Alcohol consumption, history of respiratory diseases, and pelvic surgery were not statistically significant. Variables that had P values less than 0.10 in univariate analysis entered the multivariate regression model. The results showed that age, waist circumstance, constipation,
Int Urogynecol J (2010) 21:589–593 Table 1 Logistic regression analysis models about independent risk factors of UUI
591 Risk factors
Age decile 20∼ 40∼ 60∼ Parity and mode of delivery Vaginal single delivered Vaginal multiple delivered Cesarean Nulliparity Alcohol consumption No Yes Waist circumference
