Exploring the association between lifetime physical activity and pelvic floor disorders: study and design challenges

Abstract

Background: One in four women has moderate to severe symptoms of at least one pelvic floor disorder. Lifetime physical activity, a modifiable risk factor, may theoretically predispose women to, or protect them from, developing pelvic floor disorders. It is neither feasible nor ethical to test this association using the most rigorous (level I) study design.

Purpose: The aim of this manuscript is to describe the methods for the PHysical ACtivity Study (PHACTS), which encompasses two case-control studies and the development of a registry, and to describe challenges and solutions to study progress to date. For each of the case-control studies, the primary aims are to determine, compared to controls with neither pelvic organ prolapse nor urinary incontinence, whether 1) pelvic organ prolapse or 2) stress urinary incontinence is associated with a) increased or decreased current leisure activity or b) increased or decreased overall lifetime activity (including leisure, household, outdoor, and occupational) measured in MET-hours per week, as well as in strenuous hours per week.

Methods: To obtain 175 pelvic organ prolapse cases, 175 stress urinary incontinence cases, and an equal number of age, body mass index and recruitment site matched controls, we plan to enroll 1500 women from about 20 primary care level clinics.

Results: We have encountered various challenges leading to lessons learned about minimizing bias, recruitment from community clinics, the lifetime physical activity instrument used, and data management.

Conclusions: Our experiences can help guide future investigators studying risk factors, particularly physical activity, and pelvic floor disorders.

Conflict of interest statement

Financial Disclosures

Other than funding from NIH (noted above), the authors have no financial disclosures or conflicts to report.

Copyright © 2012 Elsevier Inc. All rights reserved.

Figures

Fig. 1

A theoretical model of effects of mild/moderate vs strenuous physical activity on pelvic floor disorders. SUI= Stress Urinary Incontinence POP= Pelvic Organ Prolapse

Fig. 2

Screening and enrollment flow diagram

Fig. 3

Directed acrylic graph (DAG) illustrating effect of past physical activity on pelvic organ prolapse or stress urinary incontinence. KEY (colors are noted for black and white printing; if figure would be in color, we will change key): Open oval: unmeasured confounders in PHACTS study Light grey oval: additional confounders Dark grey circles: exposure of interest (physical activity) and outcome (POP/ SUI). Adjustment by current obesity as a proxy for past obesity is sufficient to adjust for all confounding in this DAG. Genetic propensity is not a confounder, so it is the exception to the above.