An epigenome-wide analysis of DNA methylation, racialized and economic inequities, and air pollution

Q: What hypothesis did the study test regarding DNAm and health inequities?

The study tested whether DNAm is a biological mechanism by which racial discrimination, economic adversity, and air pollution become biologically embodied.

Q: How were DNA methylation measures obtained in the two study samples?

Genome-wide DNAm was measured using Illumina EPIC BeadChip (EPIC; frozen blood spots) in one sample and Illumina 450 k BeadChip (450k; purified monocytes) in the other.

Q: Which exposure showed the strongest associations with DNAm in this analysis?

Traffic-related air pollution showed the strongest associations, including signals consistent with inflammatory processes.

Sep 28, 2026

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DNA methylation (DNAm) may link adverse social and biophysical exposures to health inequities by shaping genome regulation. This study tested whether DNAm mediates biological embodiment of racial discrimination, economic adversity, and air pollution using cross-sectional epigenome-wide association studies in two US population-based samples. Genome-wide DNAm was measured with Illumina EPIC and 450k arrays. Associations were strongest for traffic-related air pollution and showed limited replication for prior findings.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages16

Reading Time40 min

AccessFree to download

Background

Results

Conclusions

Watkins et al. Clinical Epigenetics (2026) 18:4 [https://doi.org/10.1186/s13148-025-01929-6](https://doi.org/10.1186/s13148-025-01929-6) Clinical Epigenetics RESEARCH Open Access An epigenome-wide analysis of DNA methylation, racialized and economic inequities, and air pollution Sarah Holmes Watkins1,2*, Christian Testa3,4, Andrew J. Simpkin5, George Davey Smith1,2, Brent Coull4, Immaculata De Vivo6,7, Kate Tilling1,2, Pamela D. Waterman3, Jarvis T. Chen3, Ana V. Diez‑Roux8, Nancy Krieger3, Matthew Suderman1,2 and Caroline Relton9 Abstract Background DNA methylation (DNAm) provides a plausible mechanism by which adverse exposures become embodied and contribute to health inequities, due to its role in genome regulation and responsiveness to social and biophysical exposures tied to societal context. However, scant epigenome‑wide association studies (EWAS) have included structural and lifecourse measures of exposure, especially in relation to structural discrimination. Our study tested the hypothesis that DNAm is a mechanism by which racial discrimination, economic adversity, and air pollution become biologically embodied, via a series of cross‑sectional EWAS, conducted in two population‑based samples of US‑born Black non‑Hispanic (Black NH), white non‑Hispanic (white NH), and Hispanic individuals (My Body My Story:: n = 224 Black NH and 69 white NH;; and the Multi‑Ethnic Study of Atherosclerosis:: n = 229 Black NH, n = 555 white NH and n = 191 Hispanic) . Genome‑wide changes in DNAm were measured using the Illumina EPIC BeadChip (MBMS; using frozen blood spots) and Illumina 450 k BeadChip (MESA; using purified monocytes) . Results We observed the strongest associations with traffic‑related air pollution (between 0 and 22 DNAm sites associated at p < 2.4e‑07, measured via black carbon and nitrogen oxides exposure), with evidence from both studies suggesting that air pollution exposure may induce epigenetic changes related to inflammatory processes. However, we did not replicate previous air pollution EWAS findings. We also found suggestive associations of DNAm variation with measures of structural racial discrimination (e. g. for Black NH participants, in MBMS born in a Jim Crow state associates with a DNAm site in ZNF286B at p = 8 .43E‑08; and in MESA adult exposure to racialized economic residen‑ tial segregation associates with a DNAm site in FUT6 at p = 4 . 05E‑08) situated in genes with plausible links to effects on health. Conclusions Overall, this work suggests that DNAm is a biological mechanism through which structural racism and air pollution (of which distribution of exposure is inequitable) become embodied and may lead to health inequi‑ ties. Due to the extensive range of exposures we tested, further replication in additional studies and other tissues is warranted. *Correspondence: Sarah Holmes Watkins [s.h.watkins@bristol.ac.uk](s.h.watkins@bristol.ac.uk) Full list of author information is available at the end of the article © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit [http://creativecommons.org/licenses/by/4.0/](http://creativecommons.org/licenses/by/4.0/.)[.](http://creativecommons.org/licenses/by/4.0/.) Watkins et

FAQs

What hypothesis did the study test regarding DNAm and health inequities?

The study tested whether DNAm is a biological mechanism by which racial discrimination, economic adversity, and air pollution become biologically embodied.

How were DNA methylation measures obtained in the two study samples?

Genome-wide DNAm was measured using Illumina EPIC BeadChip (EPIC; frozen blood spots) in one sample and Illumina 450 k BeadChip (450k; purified monocytes) in the other.

Which exposure showed the strongest associations with DNAm in this analysis?

Traffic-related air pollution showed the strongest associations, including signals consistent with inflammatory processes.

Sep 28, 2026

Upload by CatatanPagi