Zhang · Environment & health (Washington, D.C.) 2026 · observational cross-sectional study · n=?

Treg/Th Cell Imbalance Is Negatively Associated with Gut Microbiota Dysbiosis and Growth Impairment in Children Exposed to PFAS, PAHs, and Phthalates.

Level 4 - case-series / case-control

Cross-sectional observational study assessing correlations between pollutant biomarkers, microbiome, immune markers, and growth.

PubMed 42643665 · doi:10.1021/envhealth.5c00627 · record verified 2026-08-26

What was done

This observational study examined the relationships between exposure to environmental pollutants (PFAS, PAHs, and phthalate metabolites), gut microbiota alpha-diversity, short-chain fatty acid (SCFA) levels, Treg/effector Th cell balance, and child growth. Analyzed biomarkers included 2-OHFlu, 3-OHFlu, 2-OHNap, mBP, miBP, mEHHP, PFHxS, and PFNA. Linear regression and correlation analyses were used to assess links among pollutant levels, immune cell ratios, microbial diversity, SCFA concentrations, and Body Mass Index-for-Age Z-scores.

What was found

The abstract reports directional associations without providing exact numbers, correlation coefficients, regression estimates, or confidence intervals. Exposure to 2-OHFlu, mBP, miBP, and mEHHP was significantly associated with reduced Treg cell frequency and lower Treg/effector T cell ratios. Exposure to PFHxS, 3-OHFlu, and mBP correlated negatively with gut microbiota alpha-diversity. PFHxS, PFNA, 2-OHNap, and mBP were associated with lower SCFA levels, which positively correlated with alpha-diversity. Most SCFAs correlated negatively with the Treg/Th ratio, with valeric acid specifically associated with the Treg/Th17 ratio. Linear regression indicated that PFHxS, mBP, 3-OHFlu, and 2-OHNap were negatively associated with Body Mass Index-for-Age Z-scores.

Why it matters

This study provides human observational evidence linking concurrent exposure to multiple persistent pollutants with impaired pediatric growth through a combined microbiome, SCFA, and immune tolerance pathway.

Limits

The abstract omits sample size, participant ages, demographic details, geographic setting, and all numerical effect sizes or confidence intervals. The observational design cannot establish causality, and unmeasured confounders such as diet, socioeconomic factors, and lifestyle were not described.

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