Objective
We sought to evaluate the association between obesity and vaginal prolapse as well as pelvic organ prolapse symptoms.
Study Design
This was a cross-sectional study of women referred for urogynecologic care. The exposure was obesity and outcome, stage ≥ II prolapse. Secondary outcomes were symptom bother and disease-specific quality of life.
Results
Our study included 721 women. No difference in stage ≥ II prolapse was observed between obese (n/N = 258/721 [35.8%]) and nonobese (n/N = 463/721 [64.2%]) women (50.8% vs 52.7%; P = .62). Obesity was associated with increased distress on the Pelvic Floor Distress Inventory-20 (100 [±57.3] vs 87.4 [±53.1]; P = .003) due to higher scores on the Colorectal-Anal Distress Inventory-8 (22.9 [±21.5] vs 18.3 [±19.7]; P = .003) and the Urinary Distress Inventory-6 (48.8 [±27] vs 42.4 [±26.1]; P = .002).
Conclusion
Obesity was not associated with stage ≥ II prolapse but was associated with increased pelvic floor symptoms secondary to urinary and anal incontinence subscales.
Pelvic organ prolapse (POP) is a hernia of the vagina that occurs when the pelvic floor is no longer able to support the bowel, bladder, and/or uterus. Prolapse is a significant health concern with approximately 37% of US women presenting for routine gynecologic care experiencing stage ≥ II prolapse and 2.9% experiencing symptomatic POP. The lifetime risk of undergoing a single operation for a pelvic floor disorder approximates 11%. Age and parity are well-established risk factors for the development of POP. However, the association between obesity and prolapse severity has not been clearly defined.
The prevalence of obesity in the United States is increasing at epidemic rates. According to the Centers for Disease Control and Prevention the prevalence of obesity among adult women in 2005 through 2006 approximated 35%. Obesity has consistently been identified as a risk factor for other pelvic floor disorders such as urinary and anal incontinence.
As the prevalence of obesity increases, understanding how weight impacts the severity of POP and pelvic floor symptom bother is imperative because body weight is a modifiable risk factor. The primary objective of this study is to assess the association between obesity and stage ≥ II POP in women presenting to a tertiary center for female pelvic floor disorders. A secondary objective is to examine the association between obesity and pelvic floor symptom bother as well as disease-specific quality of life (QOL).
Materials and Methods
Institutional review board approval was obtained through Women and Infants Hospital, Providence, RI. We performed a cross-sectional study of all women seeking care for pelvic floor disorders at our institution, a tertiary urogynecology center, from May 2006 through April 2007. Results from this database have been previously published. A detailed medical history, comorbidities, physical examination, POP quantification (POPQ) measurements, height, and weight were recorded on each woman at the initial visit. Each woman was also asked to complete the short forms of the Pelvic Floor Distress Inventory (PFDI)-20 and the Pelvic Floor Impact Questionnaire (PFIQ)-7 at the time of the initial visit. Women who did not complete the PFDI-20 questionnaire or who had incomplete height/weight information were excluded. Women were also excluded if they were pregnant or had an active ostomy, previous anal sphincteroplasty, or rectovaginal fistula.
We defined exposure as obesity measured by a body mass index (BMI) ≥30 kg/m 2 consistent with guidelines outlined by the National Institutes of Health. BMI was calculated from height and weight measurements obtained at the initial visit. For our primary objective, obesity was then analyzed as a dichotomous variable (yes/no). We also explored BMI as a continuous variable to ensure that there was no discrepancy with the dichotomized classification.
We used the POPQ system to obtain standardized measurements of prolapse stage in all women at the time of their initial examination. Stage II vaginal prolapse is defined as the maximal descent of any compartment between –1 cm of the hymen to +1 cm. We defined our outcome as stage ≥ II vaginal prolapse in any compartment and included all women with maximal descent of any compartment beyond –1 cm of the hymen. Stage ≥ II prolapse was analyzed as a dichotomous variable (yes/no). We also explored the point of maximal vaginal descent, point Ba (maximal descent of the anterior compartment), point Bp (maximal descent of the posterior compartment), and point C (maximal descent of the apical compartment) as continuous variables to ensure consistency with the dichotomous classification of prolapse.
Our secondary outcomes were pelvic floor symptom bother measured by the PFDI-20 and disease-specific QOL measured by the PFIQ-7. The PFDI-20 is a validated questionnaire that measures pelvic floor symptom bother with 3 subscales: the POP Distress Inventory (POPDI)-6, the Colorectal-Anal Distress Inventory (CRADI)-8, and the Urinary Distress Inventory (UDI)-6. The range of scores for the PFDI-20, the POPDI-6, the CRADI-8, and the UDI-6 are 0-300, 0-100, 0-100, and 0-100, respectively, with higher scores indicating more symptom bother. The PFIQ-7 is a validated questionnaire that measures disease-specific QOL with 3 subscales: the POP Impact Questionnaire-7 (POPIQ-7), the Colorectal-Anal Impact Questionnaire (CRAIQ)-7, and the Urinary Impact Questionnaire (UIQ)-7. The range of scores for the PFIQ-7, the POPIQ-7, the CRAIQ-7, and the UIQ-7 are 0-300, 0-100, 0-100, and 0-100, respectively, with higher scores indicating higher disease-specific impact on QOL. The PFDI-20 summary score and subscales as well as the PFIQ-7 summary score and subscales were analyzed as continuous variables.
Descriptive statistics, Student t test, χ 2 , and Fisher’s exact test were performed as appropriate. We utilized the Shapiro-Wilk W test to confirm that POPQ variables and survey scores were not normally distributed. For the nonnormally distributed variables, we calculated the Spearman correlation coefficient ρ. Values of 0 > |ρ|> are considered to be weak correlations; therefore we did not explore these associations further. We calculated the correlation between BMI and maximal vaginal descent, point Ba, point Bp, and point C. In addition we calculated the correlation between BMI and the PFDI-20 and PFIQ-7 scores. All statistical analysis was performed using software (STATA 10.1; StataCorp, College Station, TX).
For our primary objective, we performed a sample size calculation. We assumed a prevalence of stage ≥ II POP of 40%. To detect a 15% difference between obese and nonobese women with stage ≥ II POP, a sample size calculation determined that 187 women would be needed in each group to have a power of 80% with an alpha of .05.
Results
In all, 971 women were seen as new patients during the study period; 770 women completed the PFDI-20 for a response rate of 79%. The following women were excluded: 6 due to prior anal sphincteroplasty, 3 due to active ostomy, 4 due to current fistula, 2 due to pregnancy, 1 due to male genotype, 18 due to missing height or weight, 12 due to missing POPQ measurements, and 3 due to missing charts. In all, 721 women met inclusion criteria and were included in our final analysis.
The mean age was 56.6 (±16.2) years, and 65.2% were postmenopausal ( Table 1 ). A total of 258 (35.8%) women were categorized as obese and 463 (62.2%) women were categorized as nonobese. The mean BMI of the obese group was 35.8 (±5.4) and the mean BMI of the nonobese group was 24.9 (±3.1). No difference in age, vaginal parity, race, prior pelvic surgery, or comorbidities including diabetes, hypertension, and tobacco abuse were observed between the obese and nonobese groups. Stage ≥ II prolapse was present in 375 (52.0%) women. No difference in stage II prolapse was found between obese and nonobese women (50.8% vs 52.7%; P = .62) ( Table 2 ). To further evaluate the groups, we also examined more severe prolapse, stage ≥ III, in obese and nonobese women. In all, 127 (17.6%) women had stage ≥ III prolapse. However, we found no significant difference between stage ≥ III prolapse in obese and nonobese women (16.2% vs 18.4%; P = .48).
| Characteristic | Obese (n = 258) | Nonobese (n = 463) | P value |
|---|---|---|---|
| Mean BMI, kg/m 2 (SD) | 35.8 (±5.4) | 24.9 (±3.1) | < .001 |
| Mean age, y (SD) | 57.8 (±14.5) | 55.9 (±17.0) | .93 |
| Mean vaginal parity (SD) | 2.2 (±1.58) | 2.15 (±1.58) | .68 |
| Race, n (%) | |||
| Non-Hispanic white | 204 (79.1) | 369 (79.7) | .84 |
| Menopausal, n (%) | 184 (71.3) | 286 (61.8) | .01 |
| Prior prolapse surgery, n (%) | 21 (8.14) | 37 (7.99) | .94 |
| Prior urinary incontinence surgery, n (%) | 26 (10.1) | 35 (7.56) | .24 |
| Prior hysterectomy, n (%) | 99 (38.4) | 136 (29.4) | .01 |
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