Research Studies | The Canadian Continence Foundation

Causes Of Incontience

Table of Contents

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1. 1 CHILDBIRTH

1.1.1 - Cesarean section reduces stress incontinence but not severe incontinence

1.1.2 - The relationship between incontinence after birth and trauma during delivery

1.1.3 - Having babies after age 36 increases the risk of stress urinary incontinence

1.1.4  - Factors that increase the risk of fecal incontinence in women with severe sphincter tears during childbirth

1.1.5 - Influence of childbirth and other factors on lifetime risk of moderate to severe urinary incontinence

 


1.2. HYSTERECTOMY

1.2.1 - Is urinary incontinence more common among women who have had a hysterectomy?

1.2.2 - Hysterectomy increases the risk for mild fecal incontinence

1.2.3 - Surgery for stress incontinence more than doubles among women who have had a hysterectomy

 


1.3. MENOPAUSE

1.3.1 - Menopause doesn't cause urinary incontinence, it brings improvement!

1.3.2 - Hormone replacement therapy increases the risk of urinary incontinence

1.3.3 - Pelvic floor disorders are common among women and age is not an independent risk factor

 


1.4. PROSTATE CANCER

1.4.1 - Prostate cancer and treatment increase risk for urinary and fecal incontinence

1.4.2 - The effects of radical prostatectomy and radiation on incontinence five years after treatment

1.4.3 - Urinary incontinence can worsen between two and five years after radical prostatectomy for prostate cancer


1. 1 CHILDBIRTH

1.1.1
Cesarean section reduces stress incontinence but not severe incontinence

Press J, Klein M, Kaczorowski J et al. Does cesarean section reduce postpartum urinary Incontinence? A systematic review. Birth 2007;34(3):228-37.

Why they did the study
More and more women are choosing to give birth by elective cesarean section, even when vaginal delivery is a safe option. This new trend is partly attributed to women's assumptions that vaginal delivery increases the chance of developing urinary incontinence. The medical literature on birth method and incontinence remains contradictory, as few studies have accounted for the many different variables that could be involved. Researchers at the University of British Columbia wanted to clarify the situation and provide women and their doctors with more conclusive evidence on which to base their decisions about birth method.

How they did it
The researchers conducted a systematic review of studies completed on birth method and incontinence between 1966 and 2005 to find out how often urinary incontinence occurred following cesarean section compared to vaginal birth. Two kinds of studies were included: cross-sectional studies, which measure the prevalence of a condition in a population along with risk factors thought to be associated with that condition; and cohort studies, which follow a group of people exposed to a risk factor to see what happens over time. Randomized controlled trials, which take a uniform group and assign them randomly to one option or another, provide the most conclusive evidence about the effect of one variable on outcome. But as it is unlikely that this will ever be performed in this area, cohort and cross-sectional studies are the best available.

Authors of the studies included in the review were asked to provide additional information about the type and severity of postpartum incontinence (stress, urge, mixed and unspecified urinary incontinence), the women's age at delivery and number of births (the latter two are thought to be risk factors for incontinence), and whether cesarean sections were planned or done after the woman was in labour. This new information was combined with data from the original studies and analyzed using statistical software.

What they found

  • In the six cross-sectional studies, more women had stress incontinence after vaginal delivery (16%) than after cesarean section (10%). The difference was much smaller when only severe stress incontinence was counted: 2.1% of women experienced severe incontinence after vaginal birth vs 1.3% after cesarean section. There was no difference between birth methods on the prevalence of urge incontinence.
  • In the 12 cohort studies, the risk of stress incontinence after vaginal delivery was 22%, compared to 10% after cesarean section. The incidence of severe stress incontinence was low, at 1.3% for both vaginal and cesarean deliveries. Urge and mixed incontinence occurred less often in women who had cesarean sections.
  • Longer-term cohort studies showed that elective cesareans reduced the incidence of stress urinary incontinence from 22% to 6.6%.
  • In all 18 studies, the increased risk with vaginal deliveries remained even when the use of instruments (forceps or other extraction devices) was removed, and regardless of parity (the number of prior births).

Why it matters
This review showed a decrease in the risk of developing postpartum stress urinary incontinence after cesarean section compared with vaginal delivery. Women and their doctors will have to weigh the benefits of reducing the risk of any stress incontinence from about 22% with vaginal delivery to about 6% with cesarean section against the risks and potential complications of a cesarean section to both mother and child. Women can also be reassured that severe urinary incontinence occurs in only about 1%-2% of women after birth, either vaginal or by cesarean section.

Next question
Given their findings, the authors think it is important to find out whether obstetrical practices can be improved to reduce the risk of pelvic floor injury during vaginal birth and therefore reduce the incidence of stress urinary incontinence in the years following a birth. Use of episiotomy, epidurals and the lying down (lithotomy) position are possible contributors to pelvic floor injury that could be studied further.

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1.1.2
The relationship between incontinence after birth and trauma during delivery

Williams A, Herron-Marx S, Knibb R. The prevalence of enduring postnatal perineal morbidity and its relationship to type of birth and birth risk factors.

J Clin Nurs 2007 Mar;16(3):549-61.

Why they did the study?
We know that women suffer a significant number of perineal problems following childbirth. These include urinary incontinence and fecal incontinence, but also pain and sexual problems. While women with very severe tears receive follow-up from an obstetrician and/or physiotherapist, women with smaller or no tears are assumed to be fine and receive no follow-up. Following on a 2000 statement from the United Kingdom's Royal College of Midwives that postnatal care was undervalued, the authors set out to find out more about the relationship between perineal problems following childbirth and the trauma experienced during birth.

How they did it
The authors conducted a cross-sectional community survey to explore problems experienced by women in Birmingham and Solihull, UK, one year after childbirth. They received 482 responses after sending out 2,064 questionnaires asking about different problems experienced "in the past month." The authors acknowledge that women with problems may have been more likely to respond to the questionnaire than those without.

What they found

  • One year after giving birth, 87% of women experienced some type of perineal problem.
  • 53.8% had some degree of stress incontinence and 36.6% had some degree of urge incontinence.
  • 54.5% of women reported some type of sexual problem.
  • 9.9% reported some degree of liquid fecal incontinence.
  • 32.6% of women who had an episiotomy or tear still had some degree of pain.
  • Problems are more common among women who had episiotomies or 1st or 2nd-degree tears (there were not enough women with 3rd or 4th degree tears to allow an analysis of tear severity and perineal problems).
  • 34.8% of women without perineal tears experienced stress incontinence vs 52.7 of women with a tear or episiotomy.
  • 19.5% of women without perineal tears experienced urge incontinence, vs 29.2% of women with a tear and 38% of women with episiotomy.

Why it matters
The authors point to a couple of findings as especially important:

  • First, the fact that 34.8% of women without tears or episiotomy reported new-onset stress incontinence following childbirth contradicts the assumption that problems result only from perineal trauma.
  • Second, the lack of difference in stress incontinence rates between women with 1st and 2nd degree tears and women who have an episiotomy calls into question the benefits of performing episiotomy to prevent spontaneous tear. This finding contradicts studies that relied on measures of pelvic floor strength as an indication of perineal problems, and suggests that other types of damage also contribute to symptoms such as stress incontinence, pain and sexual difficulties.

Overall, it appears that much more attention should be paid to women's perineal health in the year following childbirth, even when none of the traditionally defined birth traumas occur.

Next question
The authors think research is needed to see whether women with 3rd and 4th degree tears have greater or less risk of urinary incontinence than women who receive episiotomies. Further research is also needed into trauma unrelated to tears and episiotomies.

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1.1.3
Having babies after age 36 increases the risk of stress urinary incontinence

Groutz A, Helpman L, Gold R et al. First vaginal delivery at older age: Does it carry an extra risk for the development of stress urinary incontinence? Neurourol Urodyn 2007;26:779-82.

Why they did the study
It is increasingly common for women to have their first child after age 36. Previous studies have identified older maternal age as a risk factor for stress urinary incontinence following childbirth. The increased risk remains even when trauma to the perineal area (i.e. tears or episiotomy) do not occur. Other studies have shown that women who develop stress incontinence during pregnancy are more likely to suffer incontinence in the years following childbirth, indicating that factors of pregnancy other that birth trauma are associated with the pelvic floor disorders that contribute to urinary incontinence.

Before it is possible to make any recommendations on preventing stress incontinence among older women delivering their first child, it is important to sort out at what stage the lasting damage to the perineal area occurs. Does damage to the pelvic floor begin during pregnancy, before labour and delivery? Also, how much does maternal age itself affect the prevalence of incontinence after childbirth? The authors compared incontinence rates two years after childbirth among women over 36 years old and women under 29 years old who delivered a first child vaginally. They also compared these to rates of incontinence among women over 36 years who delivered a first child by elective cesarean section.

How they did it
The authors identified 186 women who delivered a first child at a Tel Aviv hospital by either spontaneous vaginal delivery (without the use of forceps or other instruments) or elective cesarean section. The women were interviewed one to two years after delivery regarding symptoms of stress urinary incontinence. Not included in the study were women who experienced stress incontinence before pregnancy.

What they found

  • The prevalence of stress urinary incontinence one to two years after a vaginal birth was four times more common among women who gave birth over the age of 36 (38.5%) than among women under age 29 (9.8%).
  • The prevalence of stress urinary incontinence among women over 36 who had an elective cesarean section was less than half that of older women who delivered vaginally (16.7% vs 38.5%).
  • Among older women, those who experienced stress incontinence during pregnancy were more likely to have persistent symptoms (45% vs 18% for women who had no stress incontinence during pregnancy).

Why it matters
Stress urinary incontinence is related to older age at first delivery and to pregnancy itself, not just to trauma during labour and birth. Elective cesarean section can reduce but not fully prevent incontinence in the years following childbirth. Women who experience stress urinary incontinence during pregnancy are at higher risk for lasting symptoms, whether they deliver vaginally or by elective cesarean section. Elective cesarean section can prevent further pelvic floor injury, but also carries other risks to mother and child.

Next questions
Do the protective effects of cesarean section persist as women age?
Are there protective measures that could prevent pelvic floor damage during pregnancy and delivery?

Can the group at highest risk for future incontinence be narrowed down further to provide guidance for recommending cesarean section?
What happens during pregnancy and birth to damage the pelvic floor?

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1.1.4
Factors that increase the risk of fecal incontinence in women with severe sphincter tears during childbirth

Burgio KL, Borello-France D, Richter HE et al for The Pelvic Floor Disorders Network. Risk factors for fecal and urinary incontinence after childbirth: the childbirth and pelvic symptoms study. Am J Gastroenterol 2007 Sep;102(9):1998-2004.

Why they did the study
Women who experience a sphincter tear (3rd or 4th degree) during childbirth have about double the risk of developing fecal incontinence as women who do not. However, only a minority of women develop fecal incontinence after this type of tear. As well, some women develop fecal incontinence after childbirth without sphincter tear, possibly because of unseen tears or physiologic changes that occur during pregnancy and delivery. The authors aimed to see whether maternal or obstetrical factors affected the lasting impact of childbirth on fecal incontinence, in hopes of identifying women who might be targeted for prevention or treatment efforts.

How they did it
The study looked at 759 women delivering their first child who had no history of fecal incontinence or bowel disease before pregnancy. Women were interviewed while in hospital and then by telephone six months after delivery. Information about the birth was recorded. Study participants were divided into three groups: the sphincter tear group, including women who had a 3rd or 4th degree tear that was repaired at the time of delivery; a control group of women who delivered vaginally without anal sphincter tear; a third group of women who delivered by elective cesarean section.

The authors analyzed information about the women's age, race, weight and history of incontinence during pregnancy, as well as details of the birth, to identify variables that might contribute to symptoms of fecal incontinence six months after the birth.

What they found

  • In the group of women who experienced sphincter tear, fecal incontinence six months after delivery was associated with white race, older age, higher body mass index (BMI), urinary incontinence during pregnancy, and 4th degree tears. In the vaginal delivery group without sphincter tear and the elective cesarean section group, fecal incontinence at six months was very rare and not associated any particular variables.
  • Previous studies had already found that white women faced greater risk of anal sphincter tear than black women, but this study further established that white women with sphincter tears were much more likely than black women with tears to develop fecal incontinence.
  • Age was known to be a factor in fecal incontinence. This study showed that the age effect was progressive and started well before age 40.
  • BMI is known to be a significant risk factor for fecal incontinence in the general population. This study found that BMI was only a risk factor for fecal incontinence among women who experienced a sphincter tear during childbirth. The authors suggest that higher BMI may hinder healing of the perineal area following repair of an anal sphincter tear.
  • Urinary incontinence during pregnancy was an independent risk factor for fecal incontinence 6 months after childbirth in women who had an anal sphincter tear. This may be an important marker of pelvic floor function: women with weak pelvic floor muscles may be more prone to both urinary incontinence during pregnancy and fecal incontinence following a severe tear during childbirth.

Next questions
Can early identification and treatment of women with weak pelvic floor muscles, as manifested by urinary incontinence that develops during pregnancy, reduce future problems with fecal incontinence?
What physiological or anatomical features make white women more susceptible than black women to fecal incontinence after a severe tear?

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1.1.5
Influence of childbirth and other factors on lifetime risk of moderate to severe urinary incontinence

Connolly T, Litman H, Tennstedt S et al. The effect of mode of delivery, parity, and birth weight on risk of urinary incontinence. Int Urogynecol J Pelvic Floor Dysfunct 2007; 18:1033-42.

Why they did the study
We know that childbirth is associated with a higher risk of urinary incontinence and that cesarean section is protective. It also appears that the number of pregnancies and the baby's birthweight may contribute to the risk for urinary incontinence, but studies looking at this question did not take birth method into account. The authors felt that a study looking at the number of prior deliveries, method of delivery and birthweight simultaneously was needed to guide clinical practice. Because there are also some indications that a woman's race may affect risk of urinary incontinence after childbirth, they also wanted to ensure that a racially diverse group was studied.

How they did it
The authors designed the Boston Area Community Health Survey to gather information through interviews with 3,205 women, including roughly equal numbers of black, Hispanic and white women, aged 30 to 79. The women were asked how many previous pregnancies they had, how many deliveries, the method of delivery and the birth weights of their babies. They were also asked about symptoms of urinary incontinence: 390 women were found to have symptoms of moderate/severe urinary incontinence, and 515 reported mild incontinence.
The findings were analyzed to investigate the relationships between moderate/severe incontinence and each of three reproductive factors: mode of delivery, parity (number of pregnancies) and maximum birth weight. Other variables thought to be related to incontinence, such as weight, activity levels, race, history of urinary tract infections, hysterectomy and menopause were incorporated into these analyses.

What they found

  • Women reporting urinary incontinence were more likely to be white, have a BMI over 30, be less active and have a history of urinary tract infections.
  • Women who had at least one vaginal delivery were significantly more likely to have moderate/severe incontinence compared to women who had only cesarean deliveries and women who had never been pregnant. This relationship remained strong even when BMI and urinary tract infections were controlled for. The risk did not increase with the number of deliveries.
  •  Women who had only cesarean deliveries were no more likely to have moderate/severe incontinence than women who had never been pregnant.
  • The strongest effect of mode of delivery on risk of incontinence was in the youngest age group, women between 30 and 39 years old.
  • Among women 40 and over, those who had a vaginal delivery did not have a significantly increased risk of moderate/severe incontinence compared to women who had never been pregnant. The effect of mode of delivery on risk of urinary incontinence is only significant in women aged 30-39, and not in older age groups.
  • Birth weight and number of deliveries had little effect of the risk of moderate/severe incontinence.

Why it matters

  • Several findings in this study differ from those of other research, notably that the risk for incontinence is the same for women who had cesarean section and women with no births. This may be because the authors focused only on moderate to severe urinary incontinence, eliminating mild incontinence from the analysis.
  • Also of interest is that the effect of mode of delivery is strongest among women ages 30-39 and that incontinence sometimes resolves with time.
  • Women of all races face higher risk for incontinence with vaginal delivery, although white women are at higher risk.

Next questions
Are there factors during vaginal delivery that affect risk of urinary incontinence?

Does a woman's age at first delivery affect her risk for incontinence?

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1.2. HYSTERECTOMY

1.2.1
Is urinary incontinence more common among women who have had a hysterectomy?

van der Vaart CH, van der Bom JG. The contribution of hysterectomy to the occurrence of urge and stress urinary incontinence symptoms. BJOG 2002 Feb;109(2):149-54.

Why they did the study
By age 60, up to a quarter of women have had a hysterectomy to relieve symptoms of non life-threatening conditions. Previous studies have shown that hysterectomy may be associated with the development of urinary incontinence later in life. The authors wanted to more precisely quantify how much hysterectomy increased odds of developing stress or urge incontinence following hysterectomy to help women make sound decisions.

How they did it
The authors surveyed a random sample of women 35 to 70 years old in the Netherlands. 1,626 women responded to questions about their obstetrical history, prior hysterectomy and urinary incontinence. They did not ask women who had had a hysterectomy to specify whether it was done abdominally or intravaginally. The women were asked whether they experienced stress incontinence -- "urine leakage related to physical activity, coughing or sneezing" -- or urge incontinence -- "leakage related to a feeling of urgency" -- and whether they were bothered by these symptoms.

Statistical analyses were then performed to calculate how much hysterectomy increased the odds of developing stress or urge incontinence. Other variables thought to be related to incontinence -- age, parity (number of previous pregnancies) and educational level -- were entered into the analysis one at a time to determine their effect on the relationship between incontinence and hysterectomy.

What they found

  • Among women under 60 years of age, hysterectomy increased the odds of urinary incontinence by 30% (OR 1.3).
  • Among women 60 and over, hysterectomy increased the odds of urinary incontinence by 60% (OR 1.6).
  • The association between hysterectomy and urge incontinence was not limited to women 60 and over, but was also seen among women under 60.
  • Hysterectomy did not increase the odds of developing stress urinary incontinence.

Why it matters
Urge incontinence has a negative impact on women's quality of life, even more than stress incontinence. If hysterectomy increases the risk of urge urinary incontinence, women should be counselled about this risk when they are scheduled for hysterectomy. They should be encouraged to weigh the benefits of hysterectomy in resolving uterine bleeding against the increased odds of developing urge incontinence later in life.

Next question
Why hysterectomy is a risk factor for urge urinary incontinence is not well understood. Does damage during surgery, especially to the detrusor muscle, produce bladder supersensitivity,?

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1.2.2
Hysterectomy increases the risk for mild fecal incontinence

Forsgren C, Zetterström J, Lopez A et al. Effects of hysterectomy on bowel function: a three-year, prospective cohort study. Dis Colon Rectum 2007 Aug;50(8):1139-45.

Why they did the study
The authors wanted to find out whether hysterectomy affected bowel function, including fecal incontinence and constipation. They had previously looked at problems occuring one year after hysterectomy, but wanted to find out more about longer-term effects.

How they did it
A questionnaire was completed by 120 women undergoing either vaginal or abdominal hysterectomy in Sweden. Follow-up questionnaires were answered by 115 of the women one year after the hysterectomy, and by 107 of the women three years after the hysterectomy. They were asked about bowel habits and difficulties with constipation and incontinence, using recognized questionnaires.

What they found

  • Abdominal hysterectomy was associated with a greater risk of fecal incontinence at both one-year and three-year follow-up, though the symptoms were mild.
  • Vaginal hysterectomy was not associated with increased fecal incontinence one year after a hysterectomy, but there was a significant increase at the three-year follow-up.
  • Injury to the anal sphincter during childbirth raised the risk of post-hysterectomy fecal incontinence.
  • Older age at the time of hysterectomy also increased the risk of fecal incontinence.
  • The risk of constipation and bowel emptying problems did not rise following hysterectomy.

Why it matters
Given that the increase in fecal incontinence symptom scores were mild, generally reflecting a move from "perfect" continence scores to "good" continence scores, the authors question how much impact this increase would have on women's quality of life.

Next question
The authors feel we need to take a closer look at women who suffered an anal sphincter injury during childbirth to see whether they are particularly vulnerable to further injury during hysterectomy.

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1.2.3
Surgery for stress incontinence more than doubles among women who have had a hysterectomy

Altman D, Granath F, Cnattingius S, Falconer C. Hysterectomy and risk of stress-urinary-incontinence surgery: nationwide cohort study. Lancet. 2007 Oct 27;370(9597):1494-9.

Why they did the study
Over 90% of hysterectomies are done for non life-threatening conditions such as postmenopausal bleeding. The operation is common in many countries, as it is considered a safe and effective way to cure such problems definitively. While studies have looked at rates of stress urinary incontinence following hysterectomy, the results have been inconsistent.

How they did it
The authors used surgery for stress urinary incontinence as a way to identify incontinence, thereby doing away with problems of definition and severity seen in some other studies. They used national health records to identify women who had undergone hysterectomy and see whether surgery for stress urinary incontinence was performed in the years following hysterectomy. They also identified a population of women who had not undergone hysterectomy for comparison. They excluded women who had stress incontinence surgery prior to hysterectomy. Women who had hysterectomy were matched against similar aged women who had not, and educational and parity information was collected on all the women to examine the impact of these factors on the development of stress urinary incontinence. The observation period covered 30 years.

What they found

  • The rate of surgery for stress incontinence was 179 per 100,000 women in the group that had a hysterectomy, versus 76 per 100,000 in the group that had not. This means that women who have had a hysterectomy have a 240% higher risk of requiring surgery for stress incontinence than women who have not had a hysterectomy.
  • The highest risk for requiring stress incontinence surgery occurred within five years of hysterectomy and declined after that.
  • The number of vaginal births increased the risk for stress urinary incontinence in all women, but at each number of births the risk was much higher among women who had undergone hysterectomy. After one vaginal birth, women without hysterectomy had a 2.5 fold higher risk of stress incontinence, while the risk increased six-fold among women who had a hysterectomy. After four vaginal births, the respective risks were increased 5.8 fold vs 16.5 fold.
  • Risk appeared to be greater for women who had undergone vaginal hysterectomy than those who had abdominal hysterectomy, but the difference in risk disappeared when parity was taken into account.

Why it matters
If the risk of stress urinary incontinence severe enough to require surgery more than doubles following hysterectomy, women (and the physicians who advise them) should be made aware of this risk, weigh it against the benefits of hysterectomy and perhaps contemplate other treatment methods for their benign condition before considering hysterectomy. Because the risk of incontinence increases along with the number of vaginal births, women of high parity should be even more cautious of hysterectomy.

The authors admit that using 'surgery for urinary incontinence' as a way to identify incontinence may not be valid, as women who would accept a hysterectomy in the first place may be more likely to consider surgery again. Many women suffer from incontinence but do not undergo surgery.

Next question
Are there factors that this study did not take into consideration, such as smoking, strenuous work and body mass index, that affect the risk of stress urinary incontinence after hysterectomy?

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1.3. MENOPAUSE

1.3.1
Menopause doesn't cause urinary incontinence, it brings improvement!

Waetjen LE, Feng WY, Ye J et al. Factors associated with worsening and improving urinary incontinence across the menopausal transition. Obstet Gynecol 2008 Mar;111(3):667-77.

Why they did the study
The prevalence of urinary incontinence increases in the 45-55 age range, but it is not clear why this increase occurs. Atrophy of the urogenital organs associated with lower estrogen levels after menopause has been suggested as one explanation, but others are also possible. The authors wanted to see whether the menopausal transition was in itself responsible for worsening urinary incontinence in midlife women.

How they did it
The authors selected women from the Study of Women's Health Across the Nation (SWAN) study who reported incontinenceonce a month or more at the outset of the study and at six-month follow-up. SWAN followed women aged 42 to 52 who were in pre- or perimenopause through six annual follow-up visits between 1995 and 2002. About 31% of the women reported only stress urinary incontinence, 9% reported only urge incontinence, and the remainder reported a combination of the two.

To measure improvement or deterioration in urinary incontinence, authors assigned a score at each annual visit of 0 meaning no change, +1 meaning worsening, and -1 for improving. At the end of six years, the scores were added up; women with a negative score were considered improved, those with a positive score were considered to be worsening, and women with a score of 0 were said to be unchanged.

The authors matched these measures against menopausal status and use of hormone replacement therapy at each annual visit. The other variables they looked at were weight change and change in waist-to-hip ratio.

What they found

  • 14.7% of women reported worsening of incontinence over the six years, while 32.4% reported improvement and 52.9% reported no change in the frequency of incontinence symptoms.
  • Advancing menopausal status was significantly associated with improvement in incontinence symptoms, and this held true for both stress and urge incontinence symptoms.
  • Use of hormone replacement therapy in the previous year was not associated with improvements in symptoms of stress or mixed incontinence, but starting hormone replacement therapy was associated with improvements in urge incontinence symptoms.
  • Women who reported daily or weekly symptoms in year one were more likely to see improvements over the six years.
  • Women who smoked were less likely to see improvements.
  • Women who gained weight were less likely to see improvement.

Why it matters
The study findings suggest a weak positive effect of the menopause transition on stress, urge and mixed incontinence symptoms. This goes against the belief that menopause worsens incontinence. Some other studies have found that use of hormone replacement therapy worsened stress and urge incontinence symptoms. Although the evidence was inconclusive, the present study found that starting hormones before the last menstrual period did not lower the risk of incontinence, and starting hormones at any time was only associated with improvements in urge incontinence symptoms.

Women can be reassured that there is no "inevitable" worsening of urinary incontinence symptoms in menopause, and can also be encouraged that factors they may be able to do something about, such as weight gain, can increase their chances of improving continence.

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1.3.2
Hormone replacement therapy increases the risk of urinary incontinence

Hendrix SL et al. Effects of estrogen with and without progestin on urinary incontinence. JAMA 2005;293(8):935-48.

Why they did the study
Previously, menopausal hormone therapy with estrogen alone or estrogen + progesterone was thought to have wide-ranging benefits, including improving symptoms of urinary incontinence. However, the large long-term US Women's Health Initiative (WHI) study showed an increased risk of stroke with hormone replacement therapy (HRT). Women and their doctors are now much more judicious in taking or prescribing HRT to menopausal women. The authors wanted to see what impact HRT had on the incidence and severity of urinary incontinence in postmenopausal women.

How they did it
The authors used the information collected on 23,000 women in the WHI for whom information on urinary incontinence was available at the start of the study and at one-year follow-up. Women ranged in age from 50 to 79 years, with and without prior hysterectomy, and were recruited into the study between 1993 and 1998. One group was given active estrogen + progesterone HRT, another received estrogen alone, while the other group received placebo. Information was gathered on general health status, smoking, weight and births.

What they found

  • The incidence of urinary incontinence increased overall after one year on HRT with either estrogen alone or estrogen + progesterone among women who were continent at the start of the study, and worsened among those who had some degree of urinary incontinence at the outset.
  • One year on estrogen alone more than doubled the risk of developing new stress incontinence, increased the risk for mixed incontinence by 79%, and raised the risk for urge incontinence by 32%.
  • With estrogen + progesterone, the risk for stress incontinence and mixed urinary incontinence increased by 87% and 49%, respectively, but no effect was seen on the development of urge incontinence.
  • Among women experiencing urinary incontinence at the start of the study, those taking either estrogen alone or estrogen + progesterone had a higher risk of seeing it worsen over the year than women taking placebo.

Why it matters
The increased risk for stroke found in postmenopausal women on HRT means that it should be prescribed cautiously, and only when real benefit will occur. This large study provided solid evidence that HRT provides no benefit for the prevention or treatment of urinary incontinence.
Estrogen alone and estrogen + progesterone increased the risk of urinary incontinence among continent women, and worsened symptoms of urinary incontinence among women who already suffered a degree of incontinence prior to the study. HRT should not be prescribed for the prevention or relief of urinary incontinence.

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1.3.3
Pelvic floor disorders are common among women and age is not an independent risk factor

Lawrence JM, Lukacz ES, Nager CW et al. Prevalence and co-occurrence of pelvic floor disorders in community-dwelling women. Obstet Gynecol 2008 Mar;111(3):678-85.

Why they did the study
Pelvic floor disorders -- which include urinary incontinence, overactive bladder, pelvic organ prolapse and anal incontinence (which includes flatulence only as well as fecal incontinence) -- have a very negative impact on women's quality of life. These conditions are expensive to manage and treat. However, because many women do not report them to their physicians, it is not known just how widespread these problems are among women living in the community. Also unclear is the effect of age on the prevalence of pelvic floor disorders once other variables are taken into consideration. The authors wanted to quantify the problem more precisely and see to what extent age itself was a contributor.

How they did it
A sample population of women aged 25 to 84 was identified from among Kaiser Permanente health plan members in California in 2004. A total of 4,458 women completed a questionnaire about pelvic floor disorder symptoms, births, birthweights and method of delivery, menopausal status, hormone replacement therapy use, smoking, chronic heavy lifting, weight and medical conditions. The rates of pelvic floor disorders were calculated for each age group, and then controlling for other factors.

What they found

  • 37% of the women had one or more pelvic floor disorder:
    • 15% had stress urinary incontinence
    • 13% had overactive bladder
    • 6% had pelvic organ prolapse
    • 25% had anal incontinence (almost half of these had flatulence only)
  • The prevalence of anal incontinence and overactive bladder increased significantly with age when other contributing factors were not accounted for.
  • The prevalence of stress urinary incontinence peaked among women aged 55-69 then fell in the oldest age group, again when other contributing factors were not accounted for.
  • The prevalence of pelvic organ prolapse remained stable through all age groups.
  • After adjusting for other factors (birth experience, hormone/menopause status, hysterectomy and obesity), the incidence of pelvic floor disorders no longer changed from one age group to another, with the exception of pelvic organ prolapse (more common in the 55 to 69-year-olds) and anal incontinence (more prevalent in the 40 to 54-year-olds).
  • The factors that increased the odds of each pelvic floor disorder were obesity, number of vaginal births, hormone use and history of hysterectomy.
  • Many women had more than one pelvic floor disorder: 80% of women with urinary incontinence or overactive bladder had at least one other disorder, as did 48% of women with anal incontinence.

Why it matters
The study confirmed that pelvic floor disorders are common, that they often occur together and that their overall prevalence increases with age. But they should not be considered an inevitable part of the normal aging process, as the age effect disappeared when other factors -- some of which are modifiable -- were taken into account. Doctors treating women with one reported symptom of pelvic floor disorder should be sure to inquire about others.
The authors did not ask about pelvic pain, especially dyspareunia, which affects more than 10% of women, most of whom are under 30.

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1.4. PROSTATE CANCER

1.4.1
Prostate cancer and treatment increase risk for urinary and fecal incontinence

Mols F, Korfage I, Vingerhoets J et al. Bowel, urinary and sexual problems among long-term prostate cancer survivors: A population-based study. Int J Radiat Oncol Biol Phys; 2008 Jun 4 (Epud ahead of print).

Why they did the study
A growing number of men are surviving many years with prostate cancer. The authors wanted to find out how the cancer and its treatment affected men's quality of life five and 10 years after diagnosis. Urinary and bowel problems, along with sexual function, are known to be common in the prostate cancer survivor population less than five years after diagnosis, but longer-term follow-up is needed because of increased long-term survival rates and a trend towards earlier treatment resulting from PSA testing. We do not know how much more common these problems are in prostate cancer survivors than in men of the same age without prostate cancer. Nor do we know how different treatment methods (primarily radical prostatectomy and radiation therapy) compare in terms of long-term urinary and bowel problems. The authors wanted to find out the long-term effects of prostate cancer and its different treatments on bowel, urinary and sexual function, and compare the incidence of problems to men the same age without the condition.

How they did it
The authors surveyed men under 75 years old diagnosed with prostate cancer between 1994 and 1998 in the Netherlands, along with a group of age-matched men without prostate cancer who had taken part in a screening study. The questionnaires asked men about urinary and bowel function, as well as sexual function. Information about their general health, their cancer and treatment was taken from the men's charts. In all, 547 men with prostate cancer and 3,810 men without returned the questionnaire and were included in the analysis.

What they found

  • Ten years after cancer diagnosis, urinary incontinence occurred at least once a day in 48% of patients treated with radical prostatectomy and 23% of patients treated with other methods (external beam radiation therapy, hormonal therapy or watchful waiting), compared to in 4% of the age-matched population without prostate cancer.
  • Bowel leakage occurred once a week or more in 14% of radiotherapy patients, 5%-8% of patients treated with other methods, and 2% of the age-matched population without prostate cancer.
  • Findings that urinary problems are more common after radical prostatectomy and bowel problems are more common after radiotherapy support results of shorter-term studies.

Why it matters
The study confirms that urinary and bowel problems are more common among men treated for prostate cancer than in age-matched men without cancer, even 10 years after their cancer diagnosis. Radical prostatectomy appears to produce more urinary incontinence, while external beam radiation therapy results in more bowel problems. The use of three-dimensional radiation therapy in this study may be associated with higher rates of bowel problems than intensity-modulated radiation therapy.

Because the population in the study was treated in various general hospitals rather than exclusively specialized care centres or centres of excellence, and because the response rate was so high, results can be extrapolated to the general population.

Next question
Men who received the treatments analyzed in this study differed in terms of age and the stage at which their cancer was treated. These differences may play some part in the continence-related outcomes of the therapies, but it is difficult to know this with certainty. It will also be important to learn whether newer forms of radiation therapy reduce the risk of bowel incontinence.

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1.4.2
The effects of radical prostatectomy and radiation on incontinence five years after treatment

Potosky AL, Davis WW, Hoffman RM et al. Five-year outcomes after
prostatectomy or radiation therapy for prostate cancer: the prostate cancer outcomes study. J Natl Cancer Inst 2004;96:1358–67.

Why they did the study
No studies have yet been done to compare the survival benefits of radiation therapy and radical prostatectomy for men with localized prostate cancer. In the absence of clear survival differences, the long-term impact on quality of life of each treatment option may play a larger role in a man's decision. The Prostate Cancer Outcomes Study (PCOS) examined quality of life outcomes, including incontinence, in a large group of men with prostate cancer. In this study, the authors looked at five-year quality-of-life outcomes in men participating in the PCOS to see whether differences apparent at two years persisted, improved or worsened in each treatment group.

How they did it
The PCOS conducted chart reviews of men diagnosed with prostate cancer in six American regions, and mailed a survey at six months, one year and two years following diagnosis to ask about quality of life. The present study includes the results of a five-year survey mailed to the same population. Of the 1,591 men who completed the two-year survey, 1,187 also completed the five-year survey, including 901 men who were treated with radical prostatectomy and 286 who received external beam radiation therapy (EBRT).

The authors took into account extensive information about clinical status and pre-treatment conditions and co-morbidities when looking at differences in quality of life between treatment methods. They examined the results in two ways. A cross-sectional analysis compared urinary, bowel and sexual function between treatment groups to discover the probability of experiencing problems with each treatment method. A longitudinal analysis looked at how urinary, bowel and sexual function changed over time.

What they found

  • There is little recovery in urinary control between the second and fifth year after either treatment.
  • Urinary incontinence continued to be more prevalent in the group treated with radical prostatectomy than in those who received EBRT. Five years after treatment, 15.3% of the men in the radical prostatectomy group and 4.1% of those in the EBRT group reported either "no control" or "frequently leaking urine."
  • Continent men treated with EBRT had more complaints about slow or difficult urination and urinary urgency.
  • There was no difference in the change in urinary incontinence from year two to year five between treatment groups, and this remained true regardless of their continence prior to treatment.
  • While the authors had noted a slight improvement in bowel function between the six-month survey and the two-year survey, there was little change from year two to year five in the prevalence of bowel dysfunction.
  • Bowel urgency was reported at year five by 29% of men treated with EBRT and 19% of men treated with radical prostatectomy. External beam radiotherapy also led to more problems with painful hemorrhoids (20% vs 10% of men who had radical prostatectomy).
  • There was a slight decline in bowel function from year two to year five among men treated with radical prostatectomy who had normal bowel function before treatment.
  • The difference between groups in sexual function, defined as the ability to achieve an erection, was much smaller five years after diagnosis than in the two-year survey. At two years, 82.1% of men treated with radical prostatectomy reported impotence, vs 50.3% of men treated with EBRT. By five years, the incidence dropped to 79.3% in the radical prostatectomy group, and increased to 63.5% in the EBRT group. One reason for this may have been the slightly greater chance that men treated with EBRT received androgen deprivation therapy between years 2 and 5.

Why it matters
Men facing a choice between treatment methods for localized prostate cancer should be well informed about the potential for urinary, bowel and sexual dysfunction associated with each option. Because men are living much longer after a cancer diagnosis, the evolution of these effects over time is also important. Urinary incontinence remains more troublesome for men treated with radical prostatectomy, but men treated with EBRT have a fair number of other urinary complaints. The difference in bowel function narrows slightly with time, as does the difference in sexual function. The increase in sexual difficulties between year 2 and year 5 suggests that there may be long-term effects from EBRT that need to be understood.

Next question
Treatment methods have improved since the men in this study underwent therapy in 1994-95, and new treatments such as brachytherapy have since been developed. Assessment of the effect of each therapy on urinary, bowel and sexual function must continue in order to help men make wise decisions about their management.

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1.4.3
Urinary incontinence can worsen between two and five years after radical prostatectomy for prostate cancer

Penson DF, McLerran D, Feng Z et al. 5-year urinary and sexual outcomes after radical prostatectomy: results from the Prostate Cancer Outcomes Study. J Urol 2005 May;173(5):1701-5.

Why they did the study
Prior studies have found widespread urinary incontinence and sexual dysfunction following radical prostatectomy, but these had short follow-up periods (up to two years) and did not take into account the impact of new sexual aids, the phosphodiesterase type-5 (PDE-5) inhibitors (such as Viagra®, Levitra® or Cialis®). The authors wanted to see how radical prostatectomy affected urinary and sexual function five years down the line and assess whether the availability of the PDE-5 inhibitors made a difference in sexual function.

How they did it
A population study approach was used to eliminate the chance of selection bias. Men who underwent radical prostatectomy in 1994-95 were identified from the National Cancer Institute SEER (Surveillance, Epidemiology and End Results) cancer registry and contacted for follow-up six months, one year, two years and five years after surgery. Details of their cancer and health status were taken from their charts, while urinary and sexual function was assessed through questionnaires.

What they found

  • More men reported frequent leakage of urine or no urinary control at five years than at two years (14% vs 10%). This is significantly less than the 25% who reported severe symptoms six months after prostatectomy, but still much higher than the 3.4% who experienced urinary incontinence before their prostate surgery. It would therefore appear that improvements in continence taper off after two years and that continence declines a little after that.
  • Erectile function, defined as the ability to maintain an erection sufficient for intercourse, improved somewhat between year 2 and year 5, from 22% to 28%. Nerve-sparing prostatectomy was found to increase the likelihood of being able to achieve erections, from 23% to 40%. Of the 43% of men in the group, 32% stated they achieved and maintained erections, and 13% reported that the aids helped a lot.. The authors argue that erectile aids accounted for the increase in erectile function but acknowledge that the gain could also be due to late recovery of the neurovascular bundles responsible for erection.

Why it matters
The long-term quality-of-life outcomes after radical prostatectomy are increasingly important as men survive longer with prostate cancer. Men should be aware of the risks of urinary incontinence and erectile dysfunction when they are considering initial treatment. It is also important for men and their physicians to know that the considerable improvement in urinary and sexual function seen between six months and two years after prostatectomy tapers off by year five and that incontinence may worsen somewhat after that.

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