AUTHOR=Zhang Ye , Ma Ning-Ye 

TITLE=Environmental Risk Factors for Endometriosis: An Umbrella Review of a Meta-Analysis of 354 Observational Studies With Over 5 Million Populations

JOURNAL=Frontiers in Medicine

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.680833

DOI=10.3389/fmed.2021.680833

ISSN=2296-858X

ABSTRACT=<p><bold>Background:</bold> The association between a diverse array of environmental risk factors and the risk of endometriosis is contradictory.</p><p><bold>Objective:</bold> To summarize the evidence of associations between environmental risk factors and the risk of endometriosis.</p><p><bold>Methods:</bold> Databases such as PubMed, EMBASE, Web of Science, and <ext-link ext-link-type="uri" xlink:href="https://www.clinicaltrials.gov/" xmlns:xlink="http://www.w3.org/1999/xlink">ClinicalTrial.gov</ext-link> were systematically searched in June 2020. Meta-analyses of observational studies investigated any environmental exposure (non-genetic) and endometriosis risk. For each article, we estimated the summary effect size, 95% CIs, and the 95% prediction interval (PI). We also estimated the between-study heterogeneity expressed by <italic>I</italic><sup>2</sup>, evidence for small-study effects, and evidence of excess significance bias.</p><p><bold>Results:</bold> About 12 eligible articles (featuring 143,422 cases and 5,112,967 participants) yielded data on 40 unique environmental risk factors, including life styles (<italic>n</italic> = 16), reproductive factors (<italic>n</italic> = 3), early life factors (<italic>n</italic> = 4), and a range of other risk factors [e.g., phthalate metabolites, endocrine-disrupting chemicals, and body mass index (BMI)]. About 25 of these 40 associations (62.5%) were statistically significant (<italic>p</italic> &lt; 0.05) under random-effects models. Evidence for an association was indicated for alcohol intake [relative risk (RR): 1.25; 95% CI: 1.11–1.41] and the exposure to endocrine disruptor chemicals (EDCs) (RR: 1.41; 95% CI: 1.23–1.60) while 15 associations presented only weak evidence.</p><p><bold>Conclusions:</bold> Our analyses showed that alcohol intake and exposure to endocrine-disrupting chemicals may be potential risk factors for endometriosis and supported by suggestive epidemiological evidence. However, it was evident that there was substantial heterogeneity and/or bias between the different studies featured in various meta-analyses included in this review; therefore, the outcomes of our analysis should be interpreted cautiously.</p>