Leaking Urine: Prevalence and Associated Factors in Australian Women

Transcription

1 Neurourology and Urodynamics 18: (1999) Leaking Urine: Prevalence and Associated Factors in Australian Women Pauline Chiarelli, 1 Wendy Brown, 2 * and Patrick McElduff 3 1 Faculty of Medicine and Health Sciences, The University of Newcastle, NSW, Australia 2 Research Institute for Gender and Health, The University of Newcastle, NSW, Australia 3 Department of Statistics, The University of Newcastle, NSW, Australia The Women s Health Australia project provided the opportunity to examine the prevalence of leaking urine and associated variables in three large cohorts of Australian women years of age ( young N 14,761), ( mid-age N 14,070), and ( older N 12,893). The proportion of women reporting leaking urine was 12.8% (95% CI: ), 36.1% ( ), and 35% ( ) in each of the three cohorts, respectively. Logistic regression analysis showed significant associations between leaking urine and parity in the young and mid-age women, and between leaking urine and constipation, other bowel symptoms, body mass index, and urine that burns or stings in all three groups. In the mid-age and older cohorts, women who reported having both hysterectomy and prolapse repair, or prolapse repair alone, were also more likely to report leaking urine. Lower scores on the physical and mental component summary scores of the medical outcomes survey short form (36 items) questionnaire suggest lower quality of life among women who report leaking urine, compared with those who do not. Neurourol. Urodynam. 18: , Wiley-Liss, Inc. Key words: female urinary incontinence; parity; gynaecological surgery; constipation INTRODUCTION Urinary incontinence (UI) is morbid [Grimby et al., 1993], costly [Fonda, 1992], and progressive [Ouslander, 1990] and affects women seven to eight times more often than men [Millard, 1985]. It is often presumed to be a condition experienced only in old age; one study has estimated that 50% of the 75,000 residents in Australian nursing homes (70% of whom are women) are wet [Millard, 1996]. Indeed, several epidemiological studies have shown a significant association between UI and older age [Molander et al., 1990; Burgio et al., 1991; Milsom et al,. 1993]. However, studies of UI in women across all age groups have estimated the prevalence to be between 25% [Foldspang et al., 1992] and 45% [Yarnell et al., 1981], and one 1985 study of 1,256 community dwelling adults has estimated the prevalence among Australian women over 10 years of age to be 34% [Millard, 1985]. *Correspondence to: Dr. Wendy J. Brown, Research Institute for Gender and Health, The University of Newcastle, Callaghan, NSW 2308, Australia. whwjb@cc.newcastle.edu.au Received 25 May 1998; Accepted 20 April Wiley-Liss, Inc. PROD #1062

2 568 Chiarelli et al. Parity is commonly associated with UI [Thomas and Plymat, 1980; Jolleys, 1988; Foldspang et al., 1992; Milsom et al., 1993]. Vaginal delivery has been shown to induce stretching injury to several structures within the lower part of the bony pelvis as well as to the pelvic floor muscles, nerves, and connective tissues [Snooks et al., 1984, 1985b; Swash, 1990]. In many cases, the resultant trauma may lead to poor support of the pelvic organs. Further insult to the weakened pelvic floor structures can occur in time by way of increases in abdominal pressure that accompany such conditions as constipation [Lawrence and Bannister, 1985; Laycock and Jerwood, 1991], chronic coughing or sneezing [Constantinou and Gowan, 1982; Laycock and Jerwood, 1991], and obesity [Koelbl and Riss, 1987; Wilkie, 1987]. In time these conditions are thought to lead to pelvic organ prolapse and/or urinary incontinence [Snooks et al., 1985a; Koelbl and Riss, 1987; Spence-Jones et al., 1994]. Other studies have suggested an association between urinary incontinence and other dysfunctional bowel symptoms [Coates et al., 1997; Cukier et al., 1997]. A variety of other factors has also been shown to be associated with female UI. These include hormonal status, surgery, urinary tract disorders and hereditary factors. While urinary incontinence is known to be associated with perimenopause, a study of 3,114 Danish women has found that surgical procedures contribute more strongly than menopause status to the experience of UI in middle aged women [Foldspang and Mommsen, 1994]. Significant associations between UI and urogynecological surgery have also been reported by researchers in the United States and the United Kingdom [Parys et al., 1989; Benson and McLellan 1993; Mommsen et al., 1993]. UI is also markedly increased during acute urinary tract infection (UTI) and during pregnancy. In another study of Danish women, Mommsen found that women with UTI are almost six times more likely to experience incontinence [Mommsen et al., 1994], and Chiarelli has reported the prevalence of incontinence in Australian women during pregnancy to be 64% [Chiarelli and Campbell, 1997]. UI may also be associated with hereditary factors. Studies of the prevalence of UI show a significant relationship between incontinent women and their first degree female relatives [Mushkat et al., 1996], which may be explained by a constitutional or genetic weakness in the collagen of women with bladder neck prolapse and stress incontinence of urine [Sayer, 1994]. The Australian Longitudinal Study on Women s Health [now known as the Women s Health Australia (WHA) project] provided an opportunity to determine the prevalence of leaking urine and associated factors in Australian women. The aims of this study were to examine the prevalence of the self-report of leaking urine in young, mid-age, and older Australian women; to assess the associations between leaking urine and parity, constipation and other bowel problems, body mass index (BMI), symptoms of UTI, and gynaecological surgery; and to explore differences in health related quality of life in women who do and do not report leaking urine. On the basis of previous research, it was hypothesised that the prevalence of leaking urine would increase with age and that parity, constipation, or other bowel problems, high BMI, gynaecological surgery, and symptoms of UTI (urine that burns or stings) would be associated with leaking urine. It was further hypothesised that the quality of life of women who report leaking urine would be lower than that of other women.

3 MATERIALS AND METHODS The Women s Health Australia Project The Women s Health Australia project aims to examine the relationships between biological, psychological, social and lifestyle factors, and women s physical and emotional health and the use of and satisfaction with health care services. The project involves three cohorts of women who were young (18 23 years), mid-age (45 50 years), or older (70 75 years) at the time of the baseline survey. The women were selected randomly from the national health insurance (Medicare) database, which includes all women who are resident in Australia, including women from minority ethnic groups as well as women refugees. Because there is a dearth of information about women who live outside the metropolitan areas, women who live in rural and remote areas of Australia were over sampled. Details of the recruitment methods have been described elsewhere [Brown et al., 1998]. Participants During 1996, 14,761 young women (48% of those invited to participate), 14,070 mid-age aged women (54%), and 12,893 older women (41%) completed the baseline surveys for the WHA project. The participants include women from all walks of life, living in every State and Territory of Australia. They are broadly representative of the female population of these age groups, but with over-representation of women with post-school education [Brown et al., 1998]. The Questionnaire and Measures Leaking Urine in Australian Women 569 The baseline questionnaire consisted of 252, 285, and 260 items, respectively, for the young, mid-age, and older cohorts. One of the items asked whether women had experienced leaking urine in the last year. Response options were never, rarely, sometimes, or often. Responses to this question (those answering rarely, sometimes, often) were used to estimate the prevalence of leaking urine in each cohort. Questions about other symptoms, conditions, surgical conditions, and life events varied for each cohort and included the following: all women childbirth (number of times); upper respiratory tract symptoms and conditions (allergies/hay fever/sinusitis, asthma, breathing difficulties, bronchitis/emphysema); other symptoms that can affect the pelvic floor (constipation, other bowel problems, body mass index); and symptoms or conditions that can impact on bladder control (urine that burns or stings, diabetes); mid age and older women gynaecological surgery (hysterectomy, removal of both ovaries, repair of prolapse of the uterus, bladder or bowel); and symptoms or conditions that can affect on bladder control (going through menopause, currently taking hormone replacement therapy (HRT), number of years on HRT, taking drugs for nerves or to help with sleeping difficulties, stroke). Questions about symptoms were prefixed by In the last twelve months have you experienced...?, while questions about conditions and procedures were prefixed by Have you ever been told by a doctor that you have...? or Have you ever had...?. Questions about medications were prefixed by In the past four weeks have you taken...?. The medical outcome survey short form health questionnaire (SF-36) [Ware, 1994] was used to assess general physical and mental health and well-being in each

4 570 Chiarelli et al. group. The physical and mental component summary scores (PCS and MCS) were calculated using the WHA cohort adjustment factors [Mishra and Schofield, 1998]. Data Analysis Descriptive statistics, mainly proportions and 95% confidence intervals, were calculated for self report of leaking urine in the three groups. Missing data were included in the not leaking category. For each group univariate analyses were used to explore associations between clinically plausible variables such as parity, symptoms, procedures, medications, and leaking urine. Variables that were significantly associated with leaking urine were then entered into a logistic regression model to further examine the strength of the associations between leaking urine and each of the variables, while controlling for the others. Missing data were not included. For the younger cohort the variables entered into the model were parity, constipation, other bowel problems, body mass index, and urine that burns or stings. For the mid-age and older cohorts gynaecological surgery (including removal of both ovaries, hysterectomy, and repair of prolapsed vagina, bladder, or bowel) was also included. Adjusted BMI was calculated from self report of height and weight, corrected following the method of Waters [1993]. Pairwise comparisons of the adjusted mean PCS and MCS were then computed for women in each cohort who reported leaking urine and those who did not. RESULTS The prevalence of leaking urine in the young, mid-age and older women was estimated to be 12.8% (CI: ), 36.1% (CI: ), and 35% (CI: ), respectively. Associations between self-report of leaking urine in Australian women and other reported symptoms, conditions, and life events in the younger cohort, the mid-age cohort, and the older cohort respectively are shown in Tables I III. While there was a significant association between leaking urine and parity in the younger group, this association was lessened by the impact of other conditions such as surgery in the older groups. In the young cohort, women with children and those who reported sometimes or often having urine that burns or stings were most likely to report leaking urine. There was also a strong association between constipation and leaking urine (Table I). In the mid-age cohort, women who reported urine that burns or stings, constipation, and those with high BMI were most likely to experience leaking urine. While hysterectomy alone was associated with a lower odds ratio for leaking urine, women who reported prolapse repair either alone or with hysterectomy were more likely to leak urine (Table II). In the older cohort, there was no effect for parity but all forms of surgery except solely hysterectomy were associated with leaking urine. Once again, women with the highest BMI and those reporting urine that burns or stings and constipation were most likely to report leaking urine (Table III). Adjusted mean SF-36 physical and mental component summary scores for each group are shown in Table IV. While both PCS and MCS scores were significantly

5 TABLE I. Adjusted Odds Ratios for Variables Associated With Leaking Urine in the Young Cohort Variable Never (N) Leak urine Rarely, sometimes, often (N) Adjusted a Odds ratio (95% CI) Parity Never 11,460 1, Once ( ) Twice ( ) Three or more ( ) Constipation Never 8, Rarely 2, ( ) Sometimes 1, ( ) Often ( ) Other bowel problems Never 11,308 1, Rarely ( ) Sometimes ( ) Often ( ) BMI adjusted Underweight <20 3, Ideal weight 20 <25 5, ( ) Overweight 25 <30 1, ( ) Obese ( ) Very obese > ( ) Urine that burns and stings Never 9, Rarely 2, ( ) Sometimes ( ) Often ( ) a Adjusted for all variables in the model. Leaking Urine in Australian Women 571 lower in all three age groups for women who reported leaking urine, the greatest differences were seen for MCS scores in the young and mid-age women (Table IV). DISCUSSION This was an opportunistic cross-sectional study of data collected as part of a longitudinal study. The main advantage of the study was its large sample size and the representative nature of the sample [Brown et al., 1998], while its main limitation was the use of a single non-validated question about leaking urine. However, the leaking urine question used in this survey was very similar to the validated question used by Chiarelli in her study of the prevalence of urinary incontinence during pregnancy in Australian women [Chiarelli and Campbell, 1997]. The question used did not allow differentiation between the different types of incontinence experienced by women, namely stress, urge or mixed incontinence. More than one third of the mid-age and older women reported leaking urine, with prevalence estimates for these two cohorts (36% and 35%) very similar to those reported in a community survey of women aged over 10 years (34%) [Millard, 1985],

6 572 Chiarelli et al. TABLE II. Adjusted Odds Ratios for Variables Associated With Leaking Urine in the Mid-Age Cohort Variable Never (N) Leak urine Rarely, sometimes, often (N) Adjusted a Odds ratio (95% CI) Parity Never Once ( ) Twice 3,252 1, ( ) Three or more 3,572 2, ( ) BMI adjusted: Underweight < Ideal weight 20 <25 3,926 1, ( ) Overweight 25 <30 2,490 1, ( ) Obese , ( ) Very obese > ( ) Constipation Never 4,975 1, Rarely 1,969 1, ( ) Sometimes 1,494 1, ( ) Often ( ) Other bowel problems Never 7,640 3, Rarely ( ) Sometimes ( ) Often ( ) Urine that burns and stings Never 7,427 3, Rarely 983 1, ( ) Sometimes ( ) Often ( ) Surgery b None or unknown 6,715 3, HX 1, ( ) HX + prolapse ( ) HX + OX ( ) HX + prolapse + OX ( ) Prolapse ( ) OX + prolapse ( ) OX ( ) a Adjusted for all the variables in the model. b HX, hysterectomy; OX, oophorectomy. and for women aged over 18 years participating in a general practice based survey in (37%) [Gunthorpe, 1998]. The latter study was based on an incontinence screening questionnaire, which included five carefully validated items about leaking urine. The prevalence of leaking urine in the younger cohort (12.8%) was surprisingly high and lends support to the notion that leaking urine is not necessarily a condition of old age. Notwithstanding, the higher prevalence estimate for the older cohort is likely to be lower than that for the general population of older women, as the sample comprised mostly community dwelling older women, with few women in this study living in institutional care.

7 TABLE III. Adjusted Odds Ratios for Variables Associated With Leaking Urine in the Older Cohort Variable Never (N) Leak urine Rarely, sometimes, often (N) Adjusted a Odds ratio (95% CI) Parity Never Once ( ) Twice 1, ( ) Three or more 4,278 2, ( ) Constipation Never 4,758 1, Rarely 1,232 1, ( ) Sometimes 1,206 1, ( ) Often ( ) Other bowel problems Never 6,292 2, Rarely ( ) Sometimes ( ) Often ( ) BMI adjusted Underweight < Ideal weight 20 <25 3,308 1, ( ) Overweight 25 <30 2,430 1, ( ) Obese ( ) Very obese > ( ) Urine that burns or stings Never 6,123 1, Rarely ( ) Sometimes ( ) Often ( ) Surgery b None or unknown 4,640 1, HX ( ) HX and OX ( ) HX + prolapse repair ( ) HX + prolapse repair + OX ( ) Prolapse repair ( ) OX + prolapse repair ( ) OX ( ) a Adjusted for all variabales in the model. b HX, hysterectomy; OX, oophorectomy. Leaking Urine in Australian Women 573 In the two younger cohorts, women with children were more likely to report leaking urine. The association between parity and leaking urine was strongest in the younger women, indicating that the problem may be most marked in the years immediately following pregnancy and birth. In the mid-age and older cohorts, women who reported prolapse repair either alone or in association with hysterectomy were also more likely to report leaking urine. The odds ratios for leaking urine among women in these two cohorts who reported gynaecological surgery were similar to those reported by Milsom et al. [1993] in their Danish study. Hormone replacement therapy was not seen to be protective against leaking

8 574 Chiarelli et al. TABLE IV. Means and 95% CI for SF-36 Physical and Mental Component Summary Scores in Women Who Did and Did Not Report Leaking Urine in Each Group Leak urine Young women (18 23) N 14,328 Mid-age women (45 50) N 13,022 Older women (70 75) N 10,464 Physical component summary score Rarely/sometimes/often ( ) ( ) ( ) Never ( ) ( ) ( ) Mental component summary score Rarely/sometimes/often ( ) ( ) ( ) Never ( ) ( ) ( ) urine, in either the mid-age or older women. Neither current use of HRT nor duration of use were associated with leaking urine, and adding HRT to the logistic regression made little difference to the model. The strong association between leaking urine and reports of urine that burns or stings was not surprising. Since the association was significant for each cohort, general practitioners might find treatment of UTI an opportune time to raise the issue of leaking urine with their patients, who may have previously been too embarrassed to mention that they are experiencing urinary incontinence. Similarly, for women who do raise the issue of leaking urine, general practitioners might find this an opportune time to ask about constipation, which was also strongly associated with leaking urine in each age group in this study. Repeated straining at stool is thought to weaken pelvic floor muscles and ligaments and exacerbate leakage symptoms [Lawrence and Bannister, 1985; Laycock and Jerwood, 1991]. Prevention of constipation, for example, by increasing dietary fibre, fluid intake, and physical activity, may therefore also help to alleviate the symptoms of leaking urine. In this study there was a direct relationship between leaking urine and BMI. Other researchers have suggested that increasing pressure on the pelvic floor from excess weight exacerbates leakage [Koelbl and Riss, 1987; Wilkie, 1987]. In light of this, health professionals who are encouraging women to make changes to dietary and activity patterns may be able to add the motivating reward of decreased leakage as an additional benefit of weight reduction strategies. It is also possible however that leaking urine in the months and years following childbirth may be a barrier to participation in some forms of physical activity, thus indirectly contributing to the problem of overweight and obesity in mid-age women. Researchers from the UK have correlated quality of life assessments using the SF-36 with urodynamic diagnosis of urinary incontinence in women and concluded that a number of specific urinary symptoms and urodynamic features are associated with SF-36 scores [Kelleher et al., 1994; Khullar et al., 1995]. While the lower PCS and MCS scores for women who reported leaking urine in the present study indicate an association between well being and leaking urine, these findings do not imply a direct casual relationship. There are likely to be many confounding factors. For example, in the young cohort, 9.6% of the women had one or more children. Of these, 35.6% were single parents, and in general these young single mothers reported very

9 Leaking Urine in Australian Women 575 high levels of stress and had low MCS scores. The findings may therefore reflect the fact that some of the young women with low MCS scores may have had weakened pelvic floor muscles because of recent childbirth and would therefore be more likely to experience leaking urine [Viktrup et al., 1992]. It could also be argued that chronic problems such as diabetes and stroke, which may cause leaking urine [Sotolongo, 1994], might underlie differences in the SF-36 scores between those older women who reported leaking and those who did not. However, inclusion of these chronic illnesses in the model for the older women, did not improve the model and there was no significant association between leaking urine and these problems. While many studies have looked at the efficacy of treatment protocols for curing or improving urinary incontinence once it has manifested itself, no studies have explored the efficacy of continence promotion before incontinence is experienced. In view of the associations shown here between leaking urine and parity in the young women, it would seem appropriate to explore opportunities for continence promotion with young women when they present for pregnancy care. Conservative intervention at this stage may have multiple benefits in terms of preventing incontinence, constipation, and possibly prolapse in later years. In view of the high prevalence of leaking urine among women of all ages, and its likely physical and social sequelae (which include the need for nursing home care in old age), it is clear that there is now a need for more promotion and prevention strategies to be trialed and evaluated. ACKNOWLEDGMENTS The Australian Longitudinal Study on Women s Health is funded by the (Australian) Commonwealth Department of Health and Family Services. The project was conceived and developed by groups of inter-disciplinary researchers at the Universities of Newcastle and Queensland, and the contribution of all members of the research team at the University of Newcastle, particularly the research assistants Joy Goldsworthy and Lyn Adamson, and data manager Jean Ball, is gratefully acknowledged. We would like to thank all the participants who contributed to the baseline surveys, and we are grateful to Kimberley-Clarke Pty, Ltd. for their support of this work. REFERENCES Benson J, McLellan E The effect of vaginal dissection on the pudendal nerve. Obstet Gynecol 82: Brown WJ, Bryson L, Byles J, Dobson AJ, Lee C, Mishra G, Schofield M Women s Health Australia: Recruitment for a national longitudinal cohort study. Women Health 28: Burgio KL, Matthews KA, Engel BT Prevalence, incidence and correlates of urinary incontinence in healthy middle aged women. J Urol 146: Chiarelli P, Campbell E Incontinence during pregnancy: prevalence and opportunities for continence promotion. Aust NZ J Obstet Gynaecol 37: Coates KW, Weldner AC, Cundiff JW, Elser D, Bump RC Dysfunctional bowel symptoms in women with urinary incontinence and pelvic organ prolapse. 18 th Annual Scientific Meeting of the American Urogynecologic Society. Tucson, AZ: Springer. Constantinou CE, Gowan DE Spatial distribution and timing of transmitted and reflexly generated urethral pressures in healthy women. J Urol 127:964. Cukier JM, Cortina-Borja M, Brading AF A case-control study to examine any association between ideopathic detrusor instability and gastrointestinal tract disorder, and between irritable bowel syndrome and urinary tract disorder. Br J Urol 79:

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