The role of environmental contaminants in the development of endometriosis: a systematic review.

Introduction: Several pollutants have been implicated in the etiopathogenesis of endometriosis. However, recent epidemiological studies have yielded contrasting results. With the aim to address the role of environmental contaminants on the development of endometriosis a systematic review was scrutinized through electronic databases. Methods Only articles and reviews on the association between endometriosis and pollutants on humans were included. Study design, potential biases and quality scales were analyzed for each study. Out of 481 papers identified and 46 were included and evaluated. Results: The following articles were included in our analysis: 24 devoted to polychlorinated biphenyls (PCBs) and dioxin compounds; 10 to phthalates; 5 to trace elements and heavy metals; 2 to organochlorine pesticides and bisphenols; and 1 to perfluorochemicals, particulate matter and benzophenone derivatives. Several studies indicated that dioxins and PCBs were involved in the etiopathogenesis of endometriosis. There is also evidence that PCBs and dioxins could play a role in the pathogenesis of deep endometriosis and adenomyosis. Results regarding the association between phthalates and endometriosis were contrasting. Regarding organochlorine pesticides, only β-hexachlorocyclohexane was associated with an increased odds of endometriosis. Only one study reported a significant association between perfluoro chemicals and benzophenone metabolites with endometriosis. A direct relation between trace elements and endometriosis has not been established. No association with bisphenols and particulate matter were reported. Conclusion: Relevant heterogeneity were found among studies included. Based on currently available data, an association between endometriosis and environmental pollution cannot be excluded. More prospective well-designed and less heterogeneous studies are warranted to shed light on this issue.