Association between endocrine-disrupting chemicals and thyroid cancer: a systematic review and meta-analysis

This study comprehensively evaluated the epidemiological links between five classes of endocrine-disrupting chemicals—bisphenols, polychlorinated biphenyls, organochlorine pesticides, phthalates, and per- and polyfluoroalkyl substances—and thyroid cancer risk, aiming to lay an evidence-based foundation for clarifying environmental etiology and informing public health policy. A systematic search of databases including PubMed/MEDLINE, Cochrane Library, Web of Science, and Embase was conducted up to July 22, 2025. Meta-analysis was performed using Stata 17.0, with subgroup analyses based on geographical region, pathological subtype, and covariate adjustment for factors like BMI and sex. From 1,365 initially identified articles, 22 were included, encompassing 22,916 cases. The meta-analysis revealed that PAE metabolites MEHP, MEOHP, and MEHHP had significant positive associations with thyroid cancer risk. In contrast, the PFAS perfluorooctanoic acid showed a significant negative association. No significant associations were found for bisphenols, polychlorinated biphenyls, or organochlorine pesticides. Subgroup analyses suggested that region, pathological subtype, sample type, and covariate adjustment may influence the observed associations. In conclusion, specific PAE metabolites significantly increase thyroid cancer risk, representing potential new environmental risk factors, whereas the negative correlation with PFOA requires further mechanistic investigation. The findings highlight the need to strengthen monitoring and intervention regarding PAE exposure and to promote individualized risk early warning based on pathological typing.