Risk Factors of Symptomatic Pelvic Organ Prolapse in Japanese Women

Risk Factors of Symptomatic Pelvic Prolapse Japanese Women. Abstract Aim: To estimate the prevalence, risk factors, and subjective health status of symptomatic pelvic organ prolapse in Japanese women Methods: This was a population-based cross-sectional study of 8,407 randomly selected women, aged 20–90 years. Symptomatic prolapse was self-reported by feeling of a bulge or something falling out from the vagina. Impact of the risk factors on symptomatic pelvic organ prolapse was estimated using logistic regression analysis. Multiple linear regression analysis was used to examine the association between pelvic organ prolapse symptoms and the subjective health status score. Results: Symptomatic pelvic organ prolapse was reported in 474 participants (5.6%), and the proportion of symptomatic pelvic organ prolapse cases were higher among older women and highest in those aged 70–79 years. Multivariable logistic analysis revealed a significantly higher risk of pelvic organ prolapse in women with ≥1 vaginal deliveries than in nulliparous women. Additionally, self-reported chronic medical conditions, constipation, and heavy lifting at work were strongly associated with symptomatic pelvic organ prolapse. The subjective health status was significantly impaired by pelvic organ prolapse symptoms. Conclusion: In Japanese women, the number of vaginal deliveries is a risk factor of symptomatic pelvic organ prolapse. Additionally, the symptomatic pelvic organ prolapse negatively affected the self-reported health status similar to other chronic medical conditions.


Introduction
Although pelvic organ prolapse (POP) does not directly cause severe morbidity or mortality, the pelvic floor disorders (POP, urinary and fecal incontinence, voiding, and sexual dysfunction) can adversely affect daily life, [1] health status, [2] and quality of life. [3] POP has numerous risk factors, including parity, [4] old age, [5] obesity, [6] hysterectomy, [7] chronic medical conditions, [3] heavy lifting, [8] constipation, [2] smoking, [9] employment/ occupation, [3] and race/ethnicity. [10] There is limited epidemiological data regarding symptomatic POP in Japan, despite being recognized as a disease that can be treated in outpatient or inpatient settings. This study aimed to identify the prevalence, risk factors, and subjective health status of symptomatic POP in Japanese women.
Methods the following six JA medical centers: Kumamoto and Oita centers (Kyushu, south Japan), Yamaguchi and Aichi centers (middle Japan), and Chiba and Iwate centers (north Japan). These centers were chosen through the Kumamoto University community health network. Women were considered eligible to participate in this study if they were aged >20 years and not currently pregnant. To ensure anonymity, the participants were not required to provide their name on the questionnaire and were asked to return the completed questionnaire to the researchers within 2 weeks.
The participants recorded their age (years), height (cm), and weight (kg) in the questionnaire. They then answered the following questions regarding the symptoms of POP ( "yes" to any of these questions were defined as having symptomatic

POP.
Urinary incontinence was defined as the self-reported presence of any of the following symptoms: urine leaking during sneezing or coughing, urine leaking during heavy lifting, urine leaking during the urge to toilet, difficulty in emptying the bladder, or frequent urination (>8 times during the day or >3 times at night). Positive and negative responses were assigned scores of "1" and "0," respectively.
To define the risk factors of symptomatic POP, the responses to the following questions were recorded: Were they ever examined in a hospital for their symptoms? How many times have they delivered a child? Do they have any chronic medical conditions currently being treated? What is their subjective health status? ( Table 1). The selfreported chronic medical conditions were categorized based on the total number of positive responses: 0, 1, 2, and ≥3 conditions. The self-reported health status was categorized as "excellent," "good," "fail," and "poor." Ages were categorized into groups with 10-year increments (20-29 years to ≥80 years).
Body mass index (BMI) was calculated as weight divided by height squared (kg/m2), and the participants were categorized as being normal weight (<25.0 kg/m2), overweight (25.0-30.0 kg/ m2), or obese (>30.0 kg/m2). Participants were asked to report their parity as the total number of vaginal and cesarean deliveries.

Validity of Methods
When this study was initiated, there was no validated tool for assessing symptomatic POP and the related symptoms in Japanese women. The questionnaire was constructed based on few experts' group works or modeled on several previously validated questionnaires [11][12][13][14][15][16][17][18][19] or the tools used to evaluate outpatients during gynecological visits in Japan. Based on these findings, we developed a nine-question self-reported questionnaire to identify participants with symptomatic POP ( Table 1). The internal consistency of the questionnaire was good (Cronbach's α = 0.87).
The test-retest reliability was tested, and 50 women were randomly selected from the expectation assessment group, who filled the questionnaire twice at an interval of 2 weeks (r = 0.84).  Q9: How often do you perform work-related tasks that exert force on your stomach?

Statistical Analysis
Standard methods were used for computing the mean, standard deviation (SD), and confidence interval (CI). The χ2 test was used for the analysis of nominal and ordinal data. To determine the contribution of the various proposed causes for POP, multivariate logistic regression analysis was used to control for potential confounding variables and to determine the independent associations between POP and the potential risk factors identified a priori. Urinary incontinence was excluded a priori, because it was considered a part of the outcome and associated with pelvic  show an independent association with reported symptomatic POP (Table 3).
In our study, self-reported chronic conditions, parity, and heavy lifting at work were associated with symptomatic POP.
The results are consistent with those of other population-based studies [2,9,14,27,28]. Additionally, constipation was a strong and independent risk factor of symptomatic POP, [2,29] though this association was not observed in any other study [9,30]. In our study, Age was not found to be a risk factor of symptomatic POP.
Prior studies have reported inconsistent findings regarding the association between age and POP [2,9,14,27,35]. It is possible that older women have lesser awareness of prolapse symptoms or are engaged in fewer activities that could provoke POP symptoms as compared to younger women [2]. Our results showed that about 34% women with symptomatic POP sought medical attention and health care, 46% did not, and 21% had missing data. However, no significant difference in age was noted between those who did and did not seek medical attention. This could be because the medical care and treatment for POP in the outpatient and inpatient is covered by the National Health Insurance in Japan. It is widely accepted that approximately 50% of women develop POP, but only 10-20% of them seek medical care for their condition [36].

American Journal of Biomedical Science & Research
Copy@ Chang-Nian Wei Moreover, BMI was not detected as a risk factor of symptomatic POP in this study. Previous studies reported an association between high BMI (>25 kg/m2) and POP, and overweight was considered a risk factor of symptomatic POP [9,11]. Increased BMI was associated with a high prevalence of each pelvic floor disorder. It is important to evaluate the impact of overweight and obesity on pelvic floor disorders, as this is a modifiable risk factor in a population in which the prevalence of obesity was more than 35% in 2010 [37] and 40% in 2018 [38]. In contrast with the US, 21.1% of participants had BMI >25 kg/m2 in our study ( Prior studies using multivariable logistic regression found that self-reported health status of fair or poor was strongly associated with symptomatic POP. In our study, the multiple regression model was used to determine the effect of POP on women's self-reported health status. Self-reported health status was a dependent variable and POP symptoms and chronic conditions were independent variables. POP was significantly associated with self-reported health status and had a similar effect on the women's health status as other chronic conditions did. Finally, we should pay attention to how POP affects the declining birth rate and aging society in Japan.
This study had several limitations. Because it was a crosssectional study, it could not determine the causal associations. Symptomatic POP was defined by self-reporting without confirmation by medical examination. Furthermore, the respondents were middle-aged and older women; therefore, the data may not be representative of younger women. Our study had a high non-response rate, which may have resulted in overestimation or underestimation of the actual prevalence of symptomatic POP.

Conclusion
Our results indicate that the epidemiological characteristics of POP among Japanese women predict that increase in parity, heaving lifting, constipation, and chronic conditions are its risk factors, but age, BMI, and occupation are not. Our results corroborated with those of several previous studies. Furthermore, like other chronic conditions, POP negatively affects women's health status.