Dissertation/Thesis Abstract

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Modifiable and Non-Modifiable Risk Factors for Pelvic Organ Prolapse
by Giri, Ayush, Ph.D., Vanderbilt University, 2015, 290; 13835052
Abstract (Summary)

Background and Motivation: Obesity is most likely one of the few modifiable risk factors for pelvic organ prolapse (POP). Several studies have evaluated the association between body mass index (BMI) and POP, and have reported a wide range of effect estimates ranging from negative and null to positive associations. The objectives for this study were to perform a systematic review and meta-analysis of articles published in the medical literature to: 1) provide a quantitative summary of the direction and magnitude of measures between of obesity and POP, and 2) identify potential factors which may explain heterogeneous findings across studies.

Methods: We searched PubMed for original research articles which evaluated the association between measures of obesity and POP up to June 18, 2015. Eligible studies for meta-analysis were analytical observational studies published in English that reported the risk ratios (relative risk, odds ratio or hazard ratio) for categories of body mass index (overweight and obese) in relation to POP. Inverse variance weighted random-effects models were used to evaluate and report the associations with POP from case-control, cross-sectional and cohort studies for overweight and obese BMI categories compared with women in normal-weight category (BMI < 25 kg/m2</super>). Visual examination of funnel plots and Egger’s test were used to evaluate publication bias. Sub-group analyses were performed to evaluate potential sources of heterogeneity for the following study attributes: method of POP assessment (objectively measured POP of any grade, symptomatic self-reported POP, objectively measured clinically significant POP), whether studies adjusted for key covariates (no, yes), percent of post-menopausal women in study (<33%, 33%-<67%, and ≥ 67%), whether studies used standard World Health Organization BMI categories (no, yes) and study design (cross-sectional, cohort, and case-control).

Results: A total of 22 eligible studies provided 21 effect estimates for meta-analysis of the overweight BMI category and 14 effect-estimates for meta-analysis of the obese BMI category, both compared with the normal weight category (referent: BMI < 25 kg/m2</super>). Compared with the referent BMI category, women in the overweight and obese category had meta-analysis risk ratios of at least 1.33 (95% Confidence interval [CI]: 1.16, 1.52; I2: 63%) and 1.41 (95% CI: 1.24, 1.60; I 2: 39%), respectively. We report some evidence of publication bias in one of our overweight category meta-analysis set. Subgroup analyses showed that eligible case-control studies were more likely to report larger effect estimates than cross-sectional or cohort study designs. Risk ratios for objectively measured clinically significant POP were higher than risk ratios for other measurements of POP, both in the overweight and obese analysis categories. Studies with smaller percent of post-menopausal women tended to report larger effect estimates for overweight and obese categories than studies with larger percentage of post-menopausal women. Only one eligible study included in the meta-analysis performed a prospective assessment of BMI and POP. Only two studies in the literature reported associations between waist-circumference and POP.

Conclusions: In conclusion, our meta-analysis suggests being overweight or obese increased risk for having POP compared with women who had BMI in the normal range. Mechanistic studies and larger prospective investigation of obesity measures in addition to BMI are needed to understand underlying mechanisms and establish causality.

Indexing (document details)
Advisor: Edwards, Todd L.
Commitee: Aldrich, Melinda C., Edwards, Todd L., Hartmann, Katherine E., Li, Bingshan, Velez Edwards, Digna R.
School: Vanderbilt University
Department: Epidemiology
School Location: United States -- Tennessee
Source: DAI-B 80/06(E), Dissertation Abstracts International
Subjects: Genetics, Public health, Epidemiology
Keywords: Admixture mapping, Epidemiology of POP, Gene-environment interactions, Obesity and pelvic organ prolapse, Women's health
Publication Number: 13835052
ISBN: 9780438821323
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