Environmental endocrine-disrupting chemicals as ototoxicants: a systematic review of epidemiological evidence

Hearing loss affects over 1.5 billion people globally and is projected to rise substantially by 2050. While several environmental pollutants are established ototoxicants, those that act as endocrine-disrupting chemicals (EDCs) have received far less attention as auditory hazards, despite mechanistic evidence for effects on thyroid hormone signaling, oxidative stress, and direct cochlear toxicity. No systematic review has comprehensively synthesized the human evidence linking EDC exposure to auditory outcomes. We conducted a systematic review in accordance with PRISMA 2020 guidelines (PROSPERO CRD420261383642). PubMed, Scopus, and Web of Science were searched from inception to June 10, 2026. Observational studies assessing EDC exposure through biological samples and hearing function by pure-tone audiometry or otoacoustic emissions (OAE) were eligible, and risk of bias was assessed using the Office of Health Assessment and Translation (OHAT) tool. Twenty-three studies were included (16 cross-sectional, 6 cohort, 1 case-control), encompassing ten EDC classes: polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFAS), organochlorine pesticides, organophosphates, parabens, phenols, pyrethroids, volatile organic compounds, phthalates, and polychlorinated dibenzofurans. Evidence was most consistent for PCBs, for which postnatal exposure was associated with reduced OAE amplitudes across repeated analyses of a single birth cohort, and for PFAS, with perfluorononanoic acid showing the most robust audiometric associations. Parabens and bisphenol A were associated with cochlear dysfunction in pediatric populations, though on the basis of a single research group. Within-class heterogeneity for phenols and PCBs cautioned against class-level generalizations. Overall, the evidence suggests that exposure to several EDC classes may be associated with impaired hearing in humans, supporting the inclusion of cochlear outcomes in EDC risk assessment and environmental health surveillance while underscoring the need for independent replication.