Associations of per- and polyfluoroalkyl substances and alternatives with subclinical hypothyroidism in children: A cross-sectional study in China

Luyang He; Xinhan Zhang; Peiwei Xu; Jinghao Sheng; Xiaoming Lou; Zhijian Chen; Lizhi Wu; Jie Xiang; Ping Cheng; Dandan Xu; Yuan Chen; Guangdi Chen; Xiaofeng Wang

doi:10.1016/j.scitotenv.2024.177809

Associations of per- and polyfluoroalkyl substances and alternatives with subclinical hypothyroidism in children: A cross-sectional study in China

Sci Total Environ. 2024 Nov 30:957:177809. doi: 10.1016/j.scitotenv.2024.177809. Online ahead of print.

Authors

Luyang He¹, Xinhan Zhang², Peiwei Xu², Jinghao Sheng³, Xiaoming Lou², Zhijian Chen², Lizhi Wu², Jie Xiang², Ping Cheng², Dandan Xu², Yuan Chen², Guangdi Chen⁴, Xiaofeng Wang⁵

Affiliations

¹ Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang 310051, China; School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, China.
² Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang 310051, China.
³ Department of Public Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
⁴ Department of Public Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China. Electronic address: chenguangdi@zju.edu.cn.
⁵ Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang 310051, China. Electronic address: xfwang@cdc.zj.cn.

PMID: 39616925
DOI: 10.1016/j.scitotenv.2024.177809

Abstract

There is growing experimental and epidemiological evidence linking perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure to thyroid dysfunction; however, the association between PFAS and their alternatives to subclinical hypothyroidism in children remains to be elucidated. This study investigated the association between 30 PFASs and thyroid function using serum samples from 194 children (aged 3-17 years) who participated in the Zhejiang Human Biomonitoring Program. Various thyroid function indicators, including free triiodothyronine, free thyroxine (FT4), and thyrotropin, were tested, and subclinical hypothyroidism was diagnosed. Linear regression was employed to examine the associations between individual PFASs and thyroid hormone levels, and logistic regression was applied to assess their associations with subclinical hypothyroidism. The quantile g-computation (qgcomp) method was used to examine the combined and individual effects of PFAS mixtures on thyroid function. Both PFASs and their alternatives were associated with altered thyroid hormone levels and subclinical hypothyroidism. A higher level of perfluorohexanoic acid (PFHpA) was associated with decreased FT4 with a reduction of -0.028 pmol/L (95 % confidence interval [95 % CI]: -0.047, -0.008) per unit increase as well as increased odds of subclinical hypothyroidism (odds ratio [OR] = 1.95; 95 % CI: 1.11, 3.53). Moreover, a higher PFAS mixture was associated with elevated odds of subclinical hypothyroidism (OR = 3.72; 95 % CI: 1.08, 12.85), in which PFHpA, in conjunction with 6:2 chlorinated perfluoroalkyl ether sulfonic acid, accounted for the greatest proportion of the variance. These findings augment our understanding of the adverse effects of PFASs and their alternatives on thyroid homeostasis, underscoring the need for further epidemiological research.

Keywords: Children; Joint effect; PFAS; PFAS alternatives; Thyroid function.