Risk factors associated with endometriosis: importance of study population for characterizing disease in the ENDO Study

C Matthew Peterson; Erica B Johnstone; Ahmad O Hammoud; Joseph B Stanford; Michael W Varner; Anne Kennedy; Zhen Chen; Liping Sun; Victor Y Fujimoto; Mary L Hediger; Germaine M Buck Louis; ENDO Study Working Group

doi:10.1016/j.ajog.2013.02.040

Risk factors associated with endometriosis: importance of study population for characterizing disease in the ENDO Study

Peterson CM, Johnstone EB, Hammoud AO, Stanford JB, Varner MW, Kennedy A, Chen Z, Sun L, Fujimoto VY, Hediger ML, Buck Louis GM, ENDO Study Working Group

Published June 2013 American journal of obstetrics and gynecology, 208(6), 451.e1-451.e11

DOI 10.1016/j.ajog.2013.02.040 PMID 23454253 PMC PMC4114145

RRM Academy Synopsis

Infertility history linked to higher endometriosis odds in two cohorts

A history of infertility went with higher odds of an endometriosis diagnosis in both groups studied. The ENDO Study, a matched cohort, compared 495 women having pelvic surgery with 131 women from the community of the same ages and areas. Other risk factors differed between the groups.

Key Findings

Surgeons saw endometriosis in 40% (190/473) of the operative cohort. Stage 3–4 disease made up 11.8% (56/473), and minimal or mild disease 28.3% (134/473).
MRI found probable moderate or severe endometriosis (stage 3–4) in 11% (14/127) of the population cohort.
Past infertility increased the odds of diagnosis in the operative group (AOR, 2.43; 95% CI, 1.57–3.76) and the population group (AOR, 7.91; 95% CI, 1.69–37.2).
Only in the operative group, painful periods (AOR, 2.46; 95% CI, 1.28–4.72) and pelvic pain as the reason for surgery (AOR, 3.67; 95% CI, 2.44–5.50) increased the odds.
Only in the operative group, more pregnancies (AOR, 0.49; 95% CI, 0.32–0.75), more births (AOR, 0.42; 95% CI, 0.28–0.64) and higher body mass index (AOR, 0.95; 95% CI, 0.93–0.98) lowered the odds.

Interpretation

This cohort study followed 495 women having pelvic surgery and 131 community women matched by age and area. A history of infertility raised the odds of an endometriosis diagnosis in both groups. Painful periods and pelvic pain as the reason for surgery also raised the odds in the surgical group, while more pregnancies, more births and higher body mass index lowered them. The authors note that causality remains uncertain: endometriosis and infertility may share a cause, or endometriosis may lead to infertility. The findings support larger studies of this link.

RRM Context

Restorative reproductive medicine treats infertility as a symptom to trace to an underlying condition. The ENDO Study places endometriosis among the conditions that can sit behind an infertility history. The authors describe the surgical cohort as the visible part of a larger pattern, with undiagnosed disease likely present in the wider population. A couple's trouble conceiving is a clue worth tracing.

Our editorial summary of this paper, not the article's abstract.

Abstract

Objective

We sought to identify risk factors for endometriosis and their consistency across study populations in the Endometriosis: Natural History, Diagnosis, and Outcomes (ENDO) Study.

Study Design

In this prospective matched, exposure cohort design, 495 women aged 18-44 years undergoing pelvic surgery (exposed to surgery, operative cohort) were compared to an age- and residence-matched population cohort of 131 women (unexposed to surgery, population cohort). Endometriosis was diagnosed visually at laparoscopy/laparotomy or by pelvic magnetic resonance imaging in the operative and population cohorts, respectively. Logistic regression estimated the adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for each cohort.

Results

The incidence of visualized endometriosis was 40% in the operative cohort (11.8% stage 3-4 by revised criteria from the American Society for Reproductive Medicine), and 11% stage 3-4 in the population cohort by magnetic resonance imaging. An infertility history increased the odds of an endometriosis diagnosis in both the operative (AOR, 2.43; 95% CI, 1.57-3.76) and population (AOR, 7.91; 95% CI, 1.69-37.2) cohorts. In the operative cohort only, dysmenorrhea (AOR, 2.46; 95% CI, 1.28-4.72) and pelvic pain (AOR, 3.67; 95% CI, 2.44-5.50) increased the odds of diagnosis, while gravidity (AOR, 0.49; 95% CI, 0.32-0.75), parity (AOR, 0.42; 95% CI, 0.28-0.64), and body mass index (AOR, 0.95; 95% CI, 0.93-0.98) decreased the odds of diagnosis. In all sensitivity analyses for different diagnostic subgroups, infertility history remained a strong risk factor.

Conclusion

An infertility history was a consistent risk factor for endometriosis in both the operative and population cohorts of the ENDO Study. Additionally, identified risk factors for endometriosis vary based upon cohort selection and diagnostic accuracy. Finally, endometriosis in the population may be more common than recognized.

Read the guide

Endometriosis Explained: Diagnosis, Excision Surgery, and the RRM Approach

Topics

Endometriosis › Diagnosis › Imaging · General Gynecology › Pelvic Pain › Chronic Pelvic Pain

C Matthew Peterson, Erica B Johnstone, Ahmad O Hammoud, Joseph B Stanford, Michael W Varner, Anne Kennedy, Zhen Chen, Liping Sun, Victor Y Fujimoto, Mary L Hediger, Germaine M Buck Louis

E Johnstone, A Hammoud, Joe Stanford, Joey Stanford, J Stanford, Mike Varner, M Varner, A Kennedy, Z Chen, L Sun, V Fujimoto, M Hediger, G Louis

PMID 23454253 23454253 DOI 10.1016/j.ajog.2013.02.040 10.1016/j.ajog.2013.02.040 Peterson et al. 2013, Peterson 2013

Risk factors associated with endometriosis: importance of study population for characterizing disease in the ENDO Study

Infertility history linked to higher endometriosis odds in two cohorts

Key Findings

Interpretation

RRM Context

Abstract

Read the guide

Topics

By this author

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