ORIGINAL RESEARCH article
Front. Public Health
Sec. Environmental Health and Exposome
Volume 13 - 2025 | doi: 10.3389/fpubh.2025.1603138
Serum Trihalomethanes and Cognitive Decline: Investigating Environmental Risk Factors for Neurodegenerative Diseases
Provisionally accepted
- Yancheng Third People's Hospital, Yancheng, China
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Trihalomethanes (THMs), byproducts of water chlorination, are pervasive in drinking water supplies and have known systemic toxicity. However, their potential neurotoxic effects, particularly on cognitive function, remain poorly understood. This study investigates the association between serum THM concentrations and cognitive decline, aiming to identify environmental risk factors for neurodegenerative diseases. Methods: Data were drawn from the NHANES 2011-2014 cohort. A final analytic sample of 743 participants aged 60 years or older was analyzed. Serum concentrations of four THM specieschloroform, bromodichloromethane (BDCM), dibromochloromethane, and bromoform-were measured. Cognitive performance was assessed using CERAD Word Learning and Delayed Recall, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). Cognitive impairment was defined as scores below the 25th percentile. Multivariate logistic regression, restricted cubic splines (RCS), and subgroup interaction analyses were used to explore associations.Higher serum THM concentrations were significantly associated with increased odds of cognitive impairment. In the fully adjusted model, individuals in the highest quartile of total THMs had a 2.50-fold higher risk (95% CI: 1.68-3.71) compared to the lowest quartile. RCS analysis revealed a non-linear association between BDCM and cognitive decline, particularly in the AFT. Subgroup analysis indicated that older adults (≥70 years), females, and individuals with hypertension or diabetes were more susceptible to THM-related cognitive impairment.Elevated serum THM levels are independently associated with cognitive impairment, particularly in vulnerable populations. These findings suggest that THMs may act as environmental neurotoxicants contributing to cognitive decline. Public health efforts to reduce THM exposure could play a role in mitigating the risk of neurodegenerative diseases.
Keywords: Trihalomethanes, cognitive impairment, Neurotoxicity, NHANES, Environmental Exposure
Received: 14 Apr 2025; Accepted: 09 Jun 2025.
Copyright: © 2025 Han, Liu, Wang, Song and Luo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lijian Han, Yancheng Third People's Hospital, Yancheng, China
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