This is a secondary study of a cohort designed specifically to examine pelvic floor disorders. Details of IBS and bowel function are not as clearly provided in the dataset but allowed us to estimate a prevalence of IBS among a cohort of middle-aged women and its association with the pelvic floor symptoms studied. In our cohort of 2107 racially diverse women, almost 10% of the women reported IBS. These women with IBS had more symptoms and bother from pelvic organ prolapse, and more bother from urinary incontinence, than women who did not have IBS. Sexual function in women with IBS differed from those without IBS with respect to more difficulty relaxing and lower sexual satisfaction scores. As in other published studies,(3
) the women with IBS in our cohort reported lower SF-36 scores. It is difficult to know whether the associations seen here are due to a heightened perception of symptoms in women with IBS as opposed to an actual higher prevalence of these symptoms. While some symptoms are more objective, such as number of incontinent episodes, many questions relate to “bother” from symptoms, and certainly these types of questions depend on one’s perception of pain and bother, which have been described to be elevated in people with IBS.
Our findings support that some relationship exists between IBS and conditions related to the pelvic floor. In a recent separate study examining our cohort, women with pelvic organ prolapse had 2.8 times the odds of having IBS.(17
) One hypothesis for the relationship between IBS and pelvic organ prolapse is that women with IBS may have cycles of constipation, making them prone to weakness of the pelvic floor and prolapse. Support for this hypothesis is seen in a cross-sectional study of women evaluated in a urogynecology clinic, which found that among women with stage 3 or 4 pelvic organ prolapse, 18% had IBS (95% CI 9–33%). However, there was no comparison to a healthy control group or a description of IBS prevalence in the women without prolapse.(5
) In our cohort, we found that the reported prevalence of symptomatic prolapse was higher in the women with IBS, and interestingly, they reported proportionally more bother from their prolapse symptoms than women without IBS. The nature of the data for our cohort did not provide us with adequate information to examine a subset of patients with constipation alone, to assess whether the prolapse is also correlated with constipation.
While the association of prolapse and IBS has been previously explored, few studies have focused on the relationship between IBS and urinary incontinence or urgency. In a case-control study comparing 100 consecutive outpatients with IBS (90% women) with 100 control subjects matched for age, sex, and social class, urinary frequency, urgency, nocturia, and incomplete emptying of the bladder occurred in over 50% of the IBS patients compared to 18% or less of the control group (p<0.0001).(18
) In our population-based cohort, women with IBS did not report a higher prevalence of urinary incontinence than those without IBS, although there was a higher prevalence of urinary urgency. However, again the women with IBS reported greater impact on their lifestyle from urinary incontinence symptoms. The presence of both IBS and urinary incontinence symptoms may have a greater impact on one’s lifestyle compared with the effect of urinary incontinence symptoms alone.
Women with IBS have also been described to have altered sexual function due to low interest in sex, interference with sexual activity due to their bowel symptoms, or abdominal pain.(7
) The few publications that have examined sexual dysfunction in women with IBS describe a prevalence of sexual dysfunction ranging from 24 to 83%.(7
) The women with IBS in our population-based cohort had a greater likelihood of reporting an inability to relax and enjoy sexual activity and had low sexual satisfaction. Despite these differences, they were no different from women without IBS with respect to sexual frequency, interest, arousal and ability to reach orgasm.
In one study that examined factors affecting quality of life in patients with IBS, low sexual interest and IBS symptoms interfering with sexual function were associated with a lower SF-36 mental component score.(19
) Our IBS cohort had scores similar to those found in that study, which examined a large cohort of patients with IBS at a specialty center. Of note, while the SF-36 scores for women with IBS in our study were significantly lower than for women without IBS, the clinical significance of this difference is difficult to interpret when other unmeasured variables may be modulating this effect.
Study strengths and limitations need to be considered when interpreting the results of this study. One strength of this study is that it examines a diverse cohort of women. The women in our population-based cohort are likely representative of middle-aged women with IBS. Our IBS prevalence of 10% is within the published range of 2.6–37%, especially when considering female and middle-aged subgroups.(1
) One important limitation of this study is that the diagnosis of IBS was not based on any set criteria, but was self-reported by the patient when completing a section in a standard questionnaire regarding past medical history. Therefore it is not known what proportion of the women with IBS in our cohort meet published criteria that define the syndrome. Some patients may fit under the definition of functional abdominal pain syndrome as described by Drossman et al.(25
) However, because the self-report questionnaire specifically questioned about IBS, we cannot make that assumption. We can only assume that our prevalence of IBS may capture a broader spectrum of patients with abdominal pain syndromes.
While we do have data regarding the frequency of constipation symptoms, our bowel habit questions do not elicit a history of diarrhea. The finding of a higher frequency of fecal incontinence among women with IBS could be an indicator of more diarrhea or could be unrelated. Thus, details about the subtype of IBS are also lacking, such as whether this is diarrhea or constipation predominant IBS, and it is possible that pelvic floor disorders are more prevalent in one subgroup. Severity of IBS symptoms or even the presence of current symptoms is not known. However, all questions about urinary incontinence, prolapse, and sexual function were specific to symptoms in the past 12 months, so this scope of time should encompass periods of IBS symptom activity. The temporal relationship of certain covariates such as prior operations or onset of diabetes to the diagnosis of IBS is unknown, given the nature of our data collection. We also do not know specific details of type of intestinal surgery performed. In addition, there are unmeasured covariates that may play an important role in the associations we investigated. Psychological history in addition to IBS medications, antidepressants, or other medications may affect sexual function, as may a history of sexual abuse. The latter is known to be associated with IBS and may affect the association of IBS with pelvic organ prolapse and sexual function.
In summary, this study examines the interrelationship between self-reported IBS and various pelvic organ functions in a group of middle-aged women. The symptoms we have found to be associated with IBS, including pelvic organ prolapse, urinary urgency, and sexual dysfunction, can contribute to lower quality of life, which we found in our cohort when comparing symptom bother scores and SF-36 scores between the two groups. The associations seen in this study may be due to a heightened perception or at least an increased self-awareness of symptoms among women with IBS. There is no evidence that IBS and pelvic floor symptoms are causally related, as this could only be established by performing a prospective study of women to temporally follow the course of development of IBS and pelvic floor symptoms.