Continence: Bowel and Bladder and Physical Function Decline in Women

Abstract

Purpose of review:

The purpose of this article is to review the various forms of incontinence, highlight their impact on older women, and to explore current literature regarding the link between physical activity, physical function, and incontinence.

Recent findings:

Both urinary and fecal incontinence become more prevalent with age, and are associated with significant morbidity. In parallel, there is a well-established decline in physical function that occurs with age. Furthermore, incontinence has a bidirectional relationship with physical function decline. Given the known link between increasing physical activity and preserved physical function, there is an emerging body of literature seeking to determine whether increases in physical activity may also improve incontinence outcomes. We review some recent data on this topic.

Summary:

Continence and physical function are two closely linked entities. Further research is needed to determine whether interventions that increase physical activity might result in improved continence outcomes.

Introduction

Adults achieve continence over their bladder and bowel function in childhood. With increasing age, the mechanisms responsible for continence may begin to deteriorate. There is a complex interplay between this process and the process of aging and physical function decline. Loss of the continence mechanism has a significant impact on the patient, as well as the healthcare system at large. The purpose of this review is to provide an overview of current literature on urinary and fecal incontinence as it relates to physical function decline in older adults.

Urinary Incontinence in the older woman

Urinary incontinence (UI) is defined as the involuntary loss of urine (1). The prevalence of UI is 45% in community dwelling women (2) and increases with age such that the prevalence is 51% in those 60–69 years old, 55% in those 70–79 years old and 54% in women age 80–89 (2). Prevalence is even higher in nursing home residents with estimates as high as 77% (3). Due to the increasing incidence of UI and lower urinary tract symptoms with age, there is debate regarding whether these symptoms are a “normal” part of the aging process. There is evidence of numerous changes associated with aging, which involve the detrusor, urothelium and peripheral and central nervous systems (4). However, it is currently unclear what proportion of these changes are normal versus pathologic. UI can have a significant negative impact on a woman’s quality of life. Compared to those without UI, older women with UI report increased rates of anxiety and depression (5), worse self-reported health (6), greater social isolation (7), and worse sexual dysfunction (8). UI has also been associated with nursing home admissions and mortality (9, 10).

There are two predominant categories of UI: stress urinary incontinence and urgency urinary incontinence. Stress urinary incontinence (SUI) refers to the involuntary loss of urine on effort or physical exertion, or on sneezing or coughing (1). Urgency urinary incontinence (UUI) refers to involuntary loss of urine associated with urgency (1). Mixed urinary incontinence (MUI) refers to urinary incontinence associated with urgency and also with effort or physical exertion (1). SUI is the most common subtype of UI, with studies indicating that approximately half of all incontinent women have SUI (11). However, the predominant type of UI changes with age. Between the ages of 40 and 49, SUI accounts for 60% of incontinence while mixed incontinence is less than 30%. However, as women get older, the prevalence of UUI and (MUI) increase (12). Over the age of 60, the proportion of urinary incontinence due to MUI is approximately 40%, while SUI makes up 30% of incontinence cases. (11)

The initial management of UI in older women, regardless of type, usually begins with behavioral therapy (13, 14). Women are instructed about bladder training, lifestyle modifications such as weight loss and modification of fluid and caffeine intake, and pelvic floor muscle training (PFMT) (15). PFMT is a series of exercises meant to strengthen the pelvic floor musculature to aid with urethral compression and reflexive inhibition of detrusor contractions (16). There is high quality data to support its use as a first line treatment for older women with UI (17, 18). For women with UUI, treatments with medications including antimuscarinics and beta-3 agonists can then be considered (19, 20). Use of antimuscarinics in older patients is limited by high rates of side effects including dry mouth, constipation, blurred vision and of particular concern the risk of cognitive decline (21–24). Use of these agents should be considered very carefully especially in frail older women. The most common side effect noted with beta-3 agonist therapy is hypertension and thus older women with labile hypertension should be monitored closely (25). Neuromodulation and intradetrussor botox injections can be considered for older women with refractory UUI (26). For women with SUI, incontinence pessaries and surgical options can then be considered (27).

Fecal Incontinence in the older woman

Fecal incontinence (FI), defined as the involuntary loss of feces, either solid or liquid, is a distressing condition with a significant negative impact on quality of life (1). Estimates of prevalence of FI vary widely with reported rates ranging from 1.4% to 19.5% (28–33). The prevalence of FI increases with age (32, 34) with rates over 10% in those 60–69 years old and nearly 15% in those 80–90 years old (35). Rates are significantly higher among institutionalized older adults, with estimates ranging from 20–40% in this population (31, 36). The occurrence of new onset FI in older adults is high with one study estimating an incidence rate of FI of 17% over 4 years in a population of adults 65 and older (37). To compound this even further, these estimates likely underrepresent the true prevalence and incidence as FI remains an underdiagnosed condition with several studies reporting that patients are reluctant to report symptoms due to embarrassment and other reasons (34, 38).

The negative impact of FI is well documented. Women with FI have increased rates of depression (39), social isolation (7), and self-reported poor health (34). In older adults, FI increases caregiver burden and is a significant predictor of nursing home admission (40). In addition, patient with persistent FI have an increased mortality rate compared with continent or only transiently incontinent controls (36).

Fecal continence requires coordination of multiple components including the pelvic floor and sphincter complex muscles, rectal compliance, stool consistency and cognition. Malfunction of any of these components can contribute to fecal incontinence (41). In fact, the underlying pathophysiology in FI is typically multifactorial and can include trauma (particularly obstetric trauma), neuropathy, CNS disorders, inflammatory disorders and altered stool consistency (42). Multiple risk factors exist for the development of fecal incontinence in the older woman, including: dementia, obesity, smoking, physical disability, fecal impaction, chronic diarrhea, and obstetrical trauma (43–45). It is critical to emphasize that fecal incontinence is not a normal part of the aging process and should be approached and managed as a pathologic process (46).

Management of FI in older women usually requires a multi modal approach. A thorough history and physical examination are usually the only prerequisites to begin treatment as a vast majority of patients can be managed without referral to tertiary care or invasive testing (47). Treatment usually commences with conservative measures including dietary modifications, establishing bowel regimens, and fiber supplementation. Medications including anti-diarrheal agents can be used, although given the central nervous system effects of some of these agents their use in older adults requires caution (48). Anorectal biofeedback, anal plugs, vaginal bowel control devices, anal bulking procedures and neuromodulation can then be tried (47). Surgical management is usually reserved for refractory cases and should be considered very carefully in older adults. Possible surgical approaches include sphincteroplasty, injection of bulking agents, sacral neuromodulation and colostomy however these procedures can have significant morbidity and efficacy is limited(49). There is a need for more non-invasive treatment options for management of FI in older women. Understanding the interplay of physical function and FI may provide new avenues for therapeutic interventions.

Physical Function Decline in Older Women

Although there is no standard definition, physical function can be described as a person’s ability to perform basic activities that require physical actions necessary for independent living and/or impact quality of life (50). Physical function can be assessed using self-reported subjective or objective performance-based measures. Self-reported physical function measures, usually in the form of a questionnaire, assess a woman’s perception of her physical abilities, limitations and self-efficacy (51). Examples include the Functional Status Questionnaire (FSQ) (52) and the Physical Functioning Subscale (PF-10) (53, 54). Objective measures include grip strength, the Timed Up and Go test (a test in which an individual is asked to rise from a seated position and walk a pre-defined distance, walk back and sit down again) (55), and the Short Physical Performance Battery (a well validated assessment of physical function that includes tests of gait speed (4 minute walk-test, standing balance, and chair-stand tests) (40). These objective measures may be less vulnerable to bias compared to self-reported measures, however, there is broad consensus in the geriatric literature that both are important in assessing physical function (56).

Age-related decline in physical function, along with its deleterious effects, is well documented (57). Decline in physical function predicts several worse health related outcomes including falls and physical disability (58) cognitive impairment (59), depression (60), poor cardiovascular health (61), hospitalization (62), nursing home admissions (63) and death (64). Inversely, maintenance of high physical function later in life is associated with decreased risk of mortality and disability (65). Decline in physical functioning begins in midlife and increases with age. In a study of US adults age 40 and older from the 1997–2010 National Health Interview Survey (NHIS), the estimated annual rate of increase in limitations in physical function in women was 0.7% for women age 40–64 and 1.2% for those 65 and older (66).

Urinary Incontinence and Physical Function Decline

Given that physical function declines and rates of UI increase with age, there is likely interplay between functional decline and incontinence. A plethora of cross-sectional studies have established a relationship between impaired physical function and UI in older women (67–72). More recent studies have tried to assess the temporality of physical function decline and urinary incontinence or vice versa as well as attempted to discover an underlying link to explain the relationship between physical function decline and UI.

Parker-Autry et al examined the relationship between decline in physical function and onset of UI in a secondary analysis of the Health Aging and Body Composition (Health ABC) Study (73). The Health ABC Study is a prospective, multicenter, biracial cohort study of healthy, normally functioning adults ages 70 to 79 years who contributed data on UI and underwent physical function assessment at baseline and follow up. The authors examined the decline in physical function between baseline and four-year follow up in women who developed UI versus those that did not (74). Physical performance was assessed at baseline and follow up using the Short Physical Performance Battery (SPPB), the 400-m fast-paced walk, and the 6-m usual paced walk. There were no significant differences between SPPB scores at baseline among women with and without incident UI at year four and both groups had SPPB total scores decline over time. However, the decline in SPPB total scores was significantly greater among women who developed UI compared to those women who remained continent at year four even after adjusting for baseline physical performance measures and other covariates (74). Secondarily, these authors found that incident UI increased the risk of concomitant development of sarcopenia, a decline in skeletal muscle mass, and postulated that sarcopenia may represent the link between physical function decline and urinary incontinence (74). In a previous analysis of the same database, Suskind et al reported that decline in grip strength over a three year period was associated with an increased risk of new onset predominant SUI (72). These studies suggest that declining physical function precedes the development of UI.

Some studies have investigated the impact of UI on decline in physical function. Omli et al reported on a longitudinal analysis of the Nord-Trøndelag Health study (75). In this analysis, women age 70–80 who answered questions related to UI and physical function in the study over two time periods were included. The mean period of follow-up for the participants was 11 (± 2) years. Physical function decline was defined as a decline in the activities of daily living (ADL) or instrumental activities of daily living (IADL) score in the period between baseline and the follow up visit. Urinary incontinence at baseline was significantly associated with ADL decline in older women during an eleven-year period. Incontinent women were more than twice as likely to experience decline in ADL during follow-up (OR =2.37, 95% CI=1.01–5.58, P=.04) compared to continent women. There was no significant association between urinary incontinence and IADL-decline (OR=1.18, CI=.75–1.86, P=.46) (75). Correa et al also reported on the impact of UI on physical function decline from the International Mobility in Aging Study (IMAS) (76). This study is a prospective longitudinal study whose main objective is to evaluate changes in mobility and disability in community-dwelling older adults. In this analysis, the authors evaluated change in physical function, as measured by the SPPB over 2 years in women with and without UI. The authors reported a greater decline in physical performance in women with UI compared to those without UI with a difference in the change in score between the two groups of 0.53 points (95% CI: [0.20, 0.89]). This analysis controlled for significant covariates including age, BMI, and parity.

In summary, the relationship between physical function decline and urinary incontinence in older women is likely bidirectional (Figure 1). Several hypotheses have been advanced as to why decline in physical function increases the risk of developing UI. Decreased physical function likely results in an inability to reach the bathroom quickly enough in the setting of urinary urgency. Decline in physical function may also reflect a coincident decline in skeletal muscle function with aging such that pelvic floor muscle involved in continence become weaker leading to UI (73). Correa et al have tried to explain why UI leads to decline in physical function (75). Women with UI likely avoid risks and constraints during activities of daily-living, because of the fear of losing urine involuntarily in public. Others have suggested that UI is associated with decline in physical activity such as walking and exercising and increase in sedentary activities such as sitting and watching television (86). The reduction in the frequency or intensity of physical activities ultimately leads to a greater decline in physical function over the long term which in turn increases the risk of urinary incontinence, thus establishing a cyclic relationship between the two conditions (76).

Figure 1:

Relationship between physical function decline and incontinence in older women

Fecal Incontinence and Physical Function Decline

Fewer studies have explored the relationship between declining physical function and FI. As with UI, several cross-sectional studies have demonstrated the association between impaired physical function and FI in older adults (31, 77, 78). In a study of community dwelling adults 65 and older, Quander et al examined the relationship between poor physical function and FI. In this study, physical function was measured subjectively using three questionnaires (the Katz Activities of Daily living, the Roslow-Breslau measure and the Nagi measure) and objectively using the five repeated chair stands, three tandem stands, and an eight-foot walk (77). The authors found significant associations between prevalent fecal incontinence and both the subjective and objective measures of poor physical function. In another study, Erekson et al (78) considered a population of older community-dwelling adults with monthly FI to determine the prevalence of functional disability in this population. The measures used in this study included a timed “Get up and Go” test, with an assessment of gait steadiness during the test, as well as self-reported measures of mobility. The authors found that women with FI had a significantly higher rate of compromised mobility (i.e. worsened physical function) compared to women without FI. Importantly, rates of falls and use of assistive devices were also higher in women with FI (78). Data on the temporal relationship between physical function decline and FI or vice versa is lacking. Nonetheless, similar to the bidirectional relationship with UI, it is likely that physical function decline is both a precipitant and consequence of FI. Declines in physical function likely increases a woman’s difficulty in getting to the bathroom in time and thus increases her risk of a bowel accident in the setting of fecal urgency. As previously discussed, women with FI have high rates of social isolation and are likely to avoid participating in activities. This decreased participation in activities may precipitate greater declines in physical function over time and ultimately establish a cyclic relationship between physical function and FI similar to that for UI.

Physical Activity and Physical Function in Older Women

Physical activity is defined as bodily movement produced by skeletal muscles that results in energy expenditure (79). Decades of evidence demonstrates in older adults, increased physical activity not only prevents disease but also has a positive impact of a range of health conditions (80). Furthermore, physical activity improves physical function which in turn reduces poor outcomes such as falls and fall-related injuries and contributes to older adults’ ability to maintain independence (80). Despite the well-known benefits of physical activity, rates of physical activity in adults remain low. Only 35–44% of adults over 75 reporting being physically active and only 10% meeting the physical activity requirements established in the Physical Activity Guidelines for Americans (81) (82, 83).

Physical Activity and Urinary and Fecal Incontinence

Several studies have examined the relationship between physical activity and UI and FI. There is data to suggest that increasing physical activity is associated with decreasing UI symptoms (84). One population based study indicated that higher physical activity level was independently associated with lower reported UI prevalence in an older population (over the age of 70) (85). A prospective analysis of the Nurses’ Health Study found that higher rates of physical activity was associated with a reduced risk of developing UI. Specifically, walking was associated with an approximately 25% lower risk of developing urinary incontinence (86). Compared to continent women, incontinent women tend to spend less time walking, working for pay or engaging in personal hygiene activities (87). There is similar data for FI. In different analysis of the Nurses’ Health Study, Staller et al demonstrated that higher rates of physical activity were associated with lower rates of incident FI (88).

Given the impact of physical function decline and decreased physical activity on developing UI and FI as well as the proven benefits of physical activity on improving physical function, the obvious next step is to explore the impact of interventions to increase physical activity on the prevention and treatment of UI and FI in older women. Perhaps physical activity could help to break the cycle of physical function decline leading to urinary incontinence and vice versa (figure 2). There are a few studies in the literature that explore this although this is a ripe area for research. Our group conducted a pilot study to examine the feasibility of a home-based exercise program in women age 65 and older with UI. Women were randomized to a home-based exercise program in combination with bladder and pelvic floor training versus usual care. High rates of adherence to the exercise in women in the intervention group were found. In addition, there was greater improvement in UI severity scores in the intervention group compared to usual care in as short a time period as six weeks (89). Another pilot study used a combined intervention of lifestyle/behavioral therapies (including pelvic floor physical therapy and bladder training) and a physical activity program in a population of frail older women without dementia and found that significantly more women in the intervention group had improvement in UI (90). In a randomized study comparing a twice weekly exercise regimen (including stretching, fitness, and pelvic floor muscle exercises) versus a control group that received general education classes, Kim et al similarly reported that a combined intervention of pelvic floor exercises and fitness exercises improved urine leakage scores in an older population of women (70 years and older), although this difference was greatest for those with SUI as opposed to UUI or MUI (91). A randomized controlled trial specifically considered yoga exercises tailored toward pelvic floor function compared to a control program of stretching and strengthening program (92). While this study was not powered to detect a difference between groups, women in the yoga intervention group reported improvement in urinary incontinence frequency, however, a significant difference between intervention and control groups was not observed. There is an even greater paucity of data exploring physical activity interventions in older women with fecal incontinence though one study did find that a composite intervention of exercise and prompted toileting led to an improvement in fecal incontinence frequency in a nursing home population (93). Taken together, these data provides supporting evidence for designing interventions to increase physical activity in older women with UI and FI to manage their urinary and bowel symptoms.

Figure 2:

Impact of Physical activity on physical function and incontinence in older women

Conclusion

Urinary and fecal incontinence have a significant negative impact on the quality of life of older women. The increase in the incidence of these conditions as women age is related to decline in physical function that occurs with aging. Physical activity interventions that mitigate decline in physical function may provide an intervention strategy for addressing the management and prevention of UI and FI in older women.