Associated factors to urinary incontinence in women undergoing urodynamic testing *

2 Universidade Federal de Mato Grosso do Sul, Três Lagoas, Mato Grosso do Sul, Brazil. ABSTRACT Objective: Analyzing factors associated with urinary incontinence (UI) among women submitted to urodynamic testing. Method: A cross-sectional study of 150 women attended at a urological center. Data were analyzed using univariate and multivariate statistics. Results: White women (79.3%), overweight (45.3%), menopausal (53.3%), who drink coffee (82.7%), sedentary (65.3%), who had vaginal birth (51.4%), with episiotomy (80%), and who underwent the Kristeller maneuver (69%). 60.7% had Urethral Hypermobility (UH). A statistical association was found between: weight change and UH (p = 0.024); menopause, Intrinsic Sphincter Deficiency (ISD) and Detrusor Instability (DI) (p = 0.001); gynecological surgery, ISD and DI (p = 0.014); hysterectomy and all types of UI (p = 0.040); physical activity and mixed UI (p = 0.014). Conclusion: Interventions and guidance on preventing UI and strengthening pelvic muscles should be directed at women who present weight changes, who are sedentary menopausal women, and those who have undergone hysterectomy or other gynecological surgery. Studies on pelvic strengthening methods are needed in order to take into account the profile of the needs presented by women.


INTRODUCTION
Urinary incontinence (UI) is defined by the International Continence Society (ICS) as any complaint of urine loss, regardless of the degree of social or hygienic discomfort it causes, and affects 14% to 57% of women aged between 20 and 89 years (1)(2)(3)(4) .Its higher prevalence in women stems from the lower length of the urethra, the anatomy of the pelvic floor, pregnancy and delivery, overcoming hormonal changes throughout their life cycles after ovarian follicle depletion and progressive hypoestrogenism (5)(6) .In general, the main risk factors for UI are related to sociodemographic aspects, clinical history of certain diseases, gynecological and obstetric factors, as well as life habits; especially smoking, caffeine consumption and sedentary lifestyle or intense physical activity (5)(6) .
The negative impacts of UI on women stand out in their reports such as: discomfort and embarrassment of losing urine with minimal effort, frequent trips to the bathroom, being wet and ashamed of a urine odor for stretches of time, losing urine on the way to the toilet, restricted time being away from home, having to control fluid intake, as well as family and social relationship problems.By affecting all aspects of their quality of life, such problems generate fear, shame, embarrassment and humiliation, along with physical, emotional, psychological and social consequences (1,(3)(4) .
UI is classified into: Stress urinary incontinence (SUI); Urethral hypermobility (UH); Intrinsic Sphincter Deficiency (ISD); by detrusor hyperactivity or Detrusor muscle instability (DI).In the focus of UI, Urodynamic testing (UDT) is a widely used diagnostic technique in Brazil, done in association with surveying patient's data on circumstances, frequency and severity of urine loss (7) .However, this technique is questioned due to its cost, which impedes it being carried out on a larger scale due to the discomfort and embarrassment of those who are submitted to it, and the fact that it often does not show the reported symptoms such as in cases of overactive bladders (8) .
Several studies have been carried out in Brazil regarding UI in women, however studies that address the association between types of UI and their subclassifications are still scarce, which would allow for obtaining subsidies to design diagnostic and treatment measures which can minimize or prevent the presented symptoms occurring, resulting in a better quality of life for women.
Thus, the objective of this study is to analyze the sociodemographic, health, life habits, gynecological antecedents and obstetric factors associated with urinary incontinence among women undergoing urodynamic testing.

METHOD
This is a cross-sectional quantitative research approved by the Research Ethics Committee of the São José do Rio Preto School of Medicine (FAMERP) under number 303.015, conducted with women with UI treated at a Urological Diagnosis and Treatment Center in the city of São José do Rio Preto.This center attends private patients, those with supplementary health insurance and the Brazilian Unified Health System (Sistema Único de Saúde -SUS), with an average of 100 urodynamic tests conducted on women per month.
The sample consisted of 150 women with UI undergoing urodynamic testing, selected by non-probabilistic convenience sample, and including the first 30 women who performed UDT every month between May and September 2013.Inclusion criteria adopted were: being a woman over the age of 18, not being in the gestational and puerperal periods, not having cognitive deficit and accepting to participate in the study after orientation on the study and signing of the Informed Consent Form.Those under 18 years of age or unable to read and respond to the questionnaire were excluded.
Data were collected through primary and secondary data sources.Participants responded to an instrument adapted from Higa (5) , which included variables related to gynecological history, as well as sociodemographic, obstetric, health data and lifestyle habits.UI classification was performed based on the findings of the urodynamic testing medical report, collected through a review of the participants' medical charts.
Table 2 shows a statistically significant association between the participants' type of UI and weight change, menopause, hysterectomy and physical activity.An association between ISD, DI and mixed UIs was found in postmenopausal women; those who underwent gynecological surgery had ISD and DI types of UI; while those who presented weight change and those who underwent hysterectomy had an association of all types of evaluated UI.Sedentary women had more ISD, UH and DI types of UI, and those who performed physical activity presented more mixed UI.Women with DI type UI were significantly older than those with UH type UI (Table 3).
Figure 1 shows that women with UH type UI were up to 49 years of age, had gained weight in the last 10 years, consumed coffee and had a smoking habit.On the other hand, those with mixed type UI were associated with those in one or more of the following factors: being over 50 years old, overweight, hypertensive, diuretic, diabetic, menopausal and performing some physical activity.Among women with Urinary Incontinence type DI or ISD, disorders such as neurological disease, a cough, constipation and previous gynecological surgery such as hysterectomy, perineoplasty or sling (surgery) have been reported.Table 4 shows descriptions of the obstetric variables and the UI type among the 140 women in the study, showing: mean of 2.8 gestations (SD: 1.5, minimum 1 and maximum weighed an average of 3,480g (SD: 535g: minimum 1,980 and maximum 5,300g); 48.6% had an average of 2 cesarean delivery (SD: 0.7, minimum 1 and maximum 3 deliveries); 40 (28.6%) had performed an average of 2.5 vaginal delivery (SD: 1.5, minimum 1 and maximum 8 deliveries), and 32 (22.9%) had experienced both types of delivery; 50 (69.4%)reported that they had undergone Kristeller's maneuver; 58 (80.6%) had an episiotomy, and 57 (79.2%) did not use oxytocin.Regarding the type of delivery and UI, we found: ISD (15 -10.7%) with 53.3% cesarean delivery; UH (88 -62.9%);DI type (29 -20.7%) with 62.1% vaginal delivery, and mixed UI (8 -8.7%) with 75% vaginal delivery.*Only the 72 women who had vaginal delivery were considered for these variables.

DISCUSSION
Studying the loss of urinary continence and associated factors is not only important because it represents a serious public health problem, but also because of the magnitude of suffering it causes to people affected in the physical, psychological and social spheres (1,9) .
The age of women affected by UI is revealed in several studies, showing that UI affects women across a wide age group, especially after the age of 40, with increasing incidence over the course of aging, as also evidenced in this study.In older adults, the most common type of UI is SUI, with loss of urine when coughing and sneezing (9) ; followed by DI, characterized by loss of urine before reaching the bathroom (6)(7)(8)(9)(10)(11) .SUI affects 50% of North American women, mainly women from the younger age group (11)(12) .
With regard to ethnicity, there is evidence of higher UI prevalence in white women over the different age groups (13) .Although a higher proportion of UI in white women was also identified in the present study, there is no sufficient statistical evidence to support this finding, suggesting that such an outcome may have been influenced by the predominance of the white race in the region studied.
Weight gain is associated with UI, which was also verified in this study, where body mass index (BMI) was determinant of incidence and persistence of UI (5,(14)(15) .Being overweight among older women contributes to the increase in UI symptoms, evidencing that regular physical exercise is a protective factor against UI, as it prevents obesity (12) .In this study, we observed that the majority (of the participants) did not practice physical activity, which may justify the association between all types of UI studied and women who reported gaining weight.Studies highlight the importance of physical activity for health, as well as for UI improvement, showing a higher frequency of urinary losses among less active older women (7) .On the other hand, practicing rigorous highimpact physical exercise may be a predisposing factor for the development of UI in young and nulliparous women due to the increase in intra-abdominal pressure, as evidenced in women practicing jump classes (16) .Although the present study did not measure the strength and the impact of physical exercises performed by the analyzed women, they showed a higher frequency of mixed UI.Given the importance of physical exercise and its effectiveness in treating obesity and presented as an aspect associated with UI, the need for studies with adequate design to evaluate the appearance and severity of UI according to the physical exercise profile is apparent in order to obtain subsidies for implementing specific protective measures to the exercises practiced.
Daily intake of coffee is cited as a factor for UI because caffeine can generate detrusor instability, which leads to loss of urine and a sense of voiding urgency (6) .In the present study, 82.7% of the women reported drinking coffee daily, with an average of 2.5 cups per day (SD: 2.3 cups/day and a median of 2 cups) and between 1.0 and 15.0 cups per day.
Smoking is also associated with loss of urine as tobacco leads to estrogen deficiency and smoking causes frequent coughing, facts that can lead to UI (6) .Although this study found no association between UI and intestinal constipation, some studies show its association with SUI due to the injuries it can cause to the pelvic muscles from the force/ pressure performed during evacuation (6,17) .
The association between UI and health problems is reported in several studies.The proportion of women with UI and hypertension found in this study corresponded to another study that showed the prevalence of UI in women who used diuretics (21.4%) (15) .A 2.5-fold higher association of UI among diabetics is also described, since hyperglycemia causes changes in the muscle and urethral extracellular matrix (18)(19) .
Gynecological aspects associated with UI were: menopause, explained by the hormonal changes that affect the pelvic muscles (15,20) ; perineoplasty and sling, which although presenting protective treatments to the appearance of UI, were ineffective among the women in the study; and hysterectomy, referred to as UI risk, as it may cause damage to the structures supporting the bladder and urethra (5,11,21) .
UI can be frequent in the gestational period due to the action of increasing uterine pressure and fetal weight on the pelvic floor muscles, and hormonal changes leading to a reduction in the strength of the urethral sphincter support function (20,22) .In our study, 21% of women reported UI during pregnancy.This is a lower proportion than that found in the literature which reveals that lifestyle may have had an influence and that protective measures against the appearance of UI may have been employed even before being pregnant (23)(24) .A relationship between UI in pregnancy and weight gain of pregnant women has been reported as a risk factor for pelvic floor muscle dysfunction (25) .A postpartum strategy for UI prevention is pelvic floor muscle training and postpartum weight loss (26) .It is also known that certain symptoms such as frequency, nocturia and urge incontinence (common in pregnancy) decrease significantly and tend to disappear in the postpartum period (25) .Parity has been reported as a risk factor for UI (25)(26)(27) , which was also demonstrated in this study.
Regarding the history of abortion/miscarriage in women affected by UI, there are few studies that associate this occurrence with the appearance of UI.In the present study we found that the majority of women with UI did not have a history of abortion/miscarriage (22) .
Regarding the type of delivery, it is common to assert that vaginal delivery confers a higher risk to the development of SUI in comparison to Cesarean childbirth, thus suggesting that traumas in the pelvic floor from vaginal delivery would represent a risk for development of UI.However, there is scientific evidence that indicates that well-conducted vaginal delivery is more beneficial to both mother and baby.The literature indicates equality in the prevalence of UI among women who had vaginal delivery and those with Cesarean section, reporting an even higher proportion of UI among women who only underwent Cesarean section (24)(25)(26)(27) .The frequency of UI in women who had vaginal delivery or Cesarean section in the present study was similar.
It was not found that the use of forceps was determinant for UI, although it is mentioned that the use of forceps during vaginal delivery causes more vulvoperineal laceration associated with the appearance of UI, especially SUI.We emphasize that a misuse of forceps is associated to pelvic floor dysfunctions, leading to the appearance of UI (17,(28)(29)(30) .
Epidural analgesia is cited as a risk factor for UI as it causes prolongation of the expulsive period, increasing the risk of pelvic floor injury.However, some authors consider that such anesthesia protects against UI by inducing relaxation of the pelvic floor musculature, preventing trauma during the expulsive period of vaginal delivery (5) .In this study, epidural was responsible for resolving the delivery for the majority of women.
It is recognized that heavier infants cause damage to the pelvic floor muscles, reducing the strength of the sphincter support function, which may cause mobility of the urethra and lead to incompetence of the urethral sphincter and UI.In the present study, the majority of the women had babies weighing more than 3,000g (1,25,30) .
Many complications can be reduced or prevented with appropriate obstetric care, but in Brazil, and especially in the region of São José do Rio Preto, obstetric care is exceedingly interventionist, technocratic, medicalized and hospitalcentric, resulting in owning the dishonorable title of being the world champion of caesarean sections.Common practices that undermine obstetrical care include inadequate use of oxytocin, lithotomy position at delivery, the Kristeller's maneuver, and inadequate labor guidance procedures (30) .
The cooperation of women who provided detailed information on the variables important for this study and the access to participants' medical records can be mentioned as facilities for conducting this research.As difficulties, we can point out the longer time spent in data collection due to
Even so, we consider that this research can contribute to deepening knowledge about UI and its associated factors.

CONCLUSION
The profile of the women participating in this study suggests that prevention and control of UI should be implemented through guidelines on the impact of lifestyle modifications, better control of health problems, and pelvic floor muscle strengthening practices.
Health education practices to prevent the onset of UI should be targeted for all women and can not only be carried out in primary care services, but also in private and specialized institutions/clinics.
Several studies have been carried out in Brazil regarding UI in women, however studies that address the association between types of UI and their subclassifications are still scarce.These would allow for obtaining support in designing diagnostic and treatment measures that can minimize or prevent the appearance of presented symptoms.
Data obtained in this study can provide better professional performance, especially for nurses in establishing care protocols that facilitate diagnosis, and intervention measures for prevention, treatment and control.The investigation field of UI (in women) is wide and necessary for leading to proposals and interventions which prevent and control UI disorders and improve the quality of life of affected women.

Figure 1 -
Figure 1 -Factorial analysis of the urinary incontinence types and sociodemographic, obstetric, health and lifestyle variables -São José do Rio Preto, SP, Brazil, May to Sept. 2013.

Table 1 -
Variables of sociodemographic characterization, health and life habits of women submitted to urodynamic testing -São José do Rio Preto, SP, Brazil, May to Sept. 2013.

Table 2 -
Characterization of women submitted to urodynamic testing according to the type of Urinary Incontinence presented -São José do Rio Preto, SP, Brazil, May to Sept. 2013.

Table 3 -
Age description of the women submitted to urodynamic testing according to the type of Urinary Incontinence presented -São José do Rio Preto, SP, Brazil, May to Sept. 2013.
1P value for the Analysis of Variance test (ANOVA).

Table 4 -
Obstetric variables of women submitted to urodynamic testing according to the type of urinary incontinence presented -São José do Rio Preto, SP, Brazil, May to September, 2013.