In this study on mainly white women aged 45–85 years from the general population, the prevalence of bladder and bowel disorders was high. We found a relation between the anterior compartment prolapse and urge urinary incontinence as well as a significant association between posterior compartment prolapse and bowel disorders. Analysis of the anatomical location of the POP led to these significant findings. The overall POPQ stage did not show any associations besides the symptom of vaginal bulging.
Prevalence of symptoms according to self-report questionnaires
In our overall group, the prevalence of feeling and/or seeing vaginal bulging in the overall group was 12.1%: 9.7% reported the feeling of vaginal bulging alone. These figures are comparable with the prevalence of 8.3% (95% CI 7.3–9.1) reported in a Swedish population study . In another Swedish study, only 4% had a positive POP score. However, they used other inclusion criteria and dichotomized the study population according to age and they defined a POP as a positive score on the question ‘do you experience a sense of heaviness in the lower abdomen’. . MacLennan et al. reported an 8% prevalence of POP in a general population . They defined a positive POP symptom based on the question ‘do you have a feeling of something coming down in the vagina.’
Furthermore, their age group was age 15 to ≥65 years (28% were nulliparous and the number of deliveries in the parous group was unknown). They asked all the questions in a face-to-face interview, which may have led to different answers from those given on self-report questionnaires .
Prevalence of signs scored with the POPQ grading system
In our general population, the percentage of women in the five ordinal POPQ stages (0–4) were 25%, 36.5%, 33%, 5% and 0.5%, respectively.
The prevalence of POP in a general population has only been determined using the POPQ grading system in a few studies. Our percentages in the five POP stages in the asymptomatic group 2, who did not report seeing and/or feeling vaginal bulging were comparable with those in the asymptomatic group in the study by Digesu et al. . However, there was a difference in mean age (48 years), which indicates that age may not be responsible for this comparable result, which also can be concluded from our findings that age and POP stage were not significant associated. In contrast, the data on the symptomatic group differed, probably due the different choice of definition of ‘symptomatic’. In their symptomatic group, Digesu et al. included all the women with any type of prolapse complaints, such as bladder and bowel dysfunction and those who reported a ‘sensation of dragging’ or ‘a lump or fullness in the vagina’.
In the literature, various populations of women have been studied. At first sight, the results of the prevalence of POP measured with the POPQ seems most comparable with the results reported by Swift  and Kahn , but they only recruited women who were receiving routine gynaecological health care. Thus, the characteristics of the study populations differed with respect to ethnicity, parity, BMI, age, surgical history and menopausal status, which hampers comparison of the prevalence rates in the POP stages.
In the prevalence study conducted by Nygaard et al., older women were enrolled from the Women’s Health Initiative Hormone Replacement (WHIHR) . Their results are not comparable with ours due to the different age groups, BMI and the HRT (mean age 68.2 years, BMI 30.4). Furthermore, according to Nygaard et al., some degree of POP is nearly ubiquitous in older women. However, in our study, we did not observe a significant increase in POP with increasing age. The differences can probably be explained by patient selection, with different HRT scores, BMI and heavy physical work [26, 27] in the population studied by Nygaard et al.
In our study, POP complaints were present in 3.8% of the nulliparous women. This indicates that childbirth is not a prerequisite for POP, although Boyle et al. demonstrated that pregnancy was associated with increased POP stages compared to nulliparous women . In our study, the median parity in the symptomatic and asymptomatic groups was similar (2). In the vaginal examination group, there was a significant (p 0.002) increase in POP with increasing parity, especially after the second child (OR 1.8). This is in line with the study by Mant et al.  who demonstrated that women with two children were 8.4 times more likely to develop POP that required hospital admission.
Pelvic floor symptoms versus POP signs measured with the POPQ, analysed with the grading system 0–4
In our study, no significant correlations were found between the pelvic floor symptoms of bladder and/or bowel disorders. However, we did find a significant correlation with ‘seeing and/or feeling vaginal bulging’. Similar to the results of many other studies [10, 13, 21], we observed strong discrepancies between the symptoms and signs. Therefore, we emphasise the need for a clinically relevant definition of POP that is not only based on anatomical findings, but also on the symptoms.
Pelvic floor symptoms versus POP location measured with the POPQ, analysed with the nine-point notation
Although no significant correlations could be demonstrated between the pelvic floor symptoms and the ordinal POP stage (0-4 of the POPQ), many significant correlations were found between the anatomical locations of the nine-point notation. The presence of urge urinary incontinence was significantly associated with the lowest point of the upper anterior vaginal wall. This has been demonstrated in earlier studies and urge urinary incontinence disappeared or diminished after successful surgical correction of the anterior vaginal wall .
Our results differed from those reported by Bradley et al. . Bladder pain and obstructive bladder symptoms were significantly associated with the lowest point of the upper anterior vaginal wall, but not with the presence of urge urinary incontinence. Overall, most of the significant associations were with obstructive bowel disorders: feeling of anal prolapse, manual evacuation of stool per vagina and per anus. Constipation and vaginal bulging were significantly associated with apical support and the genital hiatus. This is in line with the findings reported by Klingele et al. . POP severity was lower in their faecal incontinence group than in their obstructive bowel symptom group. The study by Bradley also demonstrated that vaginal bulging was associated with point C . Our point C results contrasted with the study by Kahn , in which they did not find any significant association with constipation. However, Kahn et al. reported similar results on the need for manual evacuation of stool and straining associated with the lowest point on the upper posterior vaginal wall (point Bp). Therefore, the posterior vaginal wall is strongly associated with bowel disorders, including incontinence of flatus. It is likely that anatomical changes in the posterior vaginal wall are partly responsible for this symptom.
To analyse associations between POP symptoms and signs and bladder/bowel disorders in a general population, the POPQ grading system did not show as many significant associations as the nine-point notation. This is not surprising because the POPQ grading system only takes the most severely prolapsed compartment into account, which is not necessarily the compartment responsible for the most relevant symptoms. This demonstrates the need to present details about compartments when reporting on the prevalence of POP.
Strengths and limitations
POP varies between different ethnicities . One of the strengths of our study was the ethnic homogeneity, because almost all of the women were white, which eliminated racial bias in the results. Furthermore, broad data were obtained from a large study group using a combination of questionnaires and vaginal examination.
Although this study was performed on a general population, the mean BMI of 25 and the 98% white race may have negative effects on extrapolation to other general populations. Also some selection bias could be present due to the women who participated in a vaginal examination and perhaps were symptomatic and never sought help in the past. Our data demonstrated important associations between bladder/bowel disorders and POP that will help to support the development of preventive strategies for pelvic floor disorders.