Abstract
Residential segregation is associated with differential exposure to air pollution. Hippocampus structure and function are highly susceptible to pollutants and associated with posttraumatic stress disorder (PTSD) development. Therefore, we investigated associations between residential segregation, air pollutants, hippocampal neurobiology, and PTSD in recent trauma survivors. Participants (N = 278; 34% non-Hispanic white, 46% Non-Hispanic Black, 16% Hispanic) completed multimodal neuroimaging two weeks after trauma. Yearly averages of air pollutants (PM2.5 and NO2) and racial/economic segregation (Index of Concentration at the Extremes) were derived from each participant’s address. Linear models assessed if air pollutants mediated associations between segregation and hippocampal volume, threat reactivity, or parahippocampal cingulum fractional anisotropy (FA) after covarying for age, sex, income, and 2-week PTSD symptoms. Further models evaluated if pollutants or segregation prospectively predicted PTSD symptoms six months post-trauma. We found that non-Hispanic Black participants lived in neighborhoods with significantly greater segregation and air pollution compared to Hispanic and non-Hispanic white participants (ps < 0.001). PM2.5 concentration was positively correlated with threat reactivity (r(276) = 0.16, p < 0.006), while NO2 concentration was positively correlated with hippocampus volume (r(276) = 0.17, p < 0.005) and negatively correlated with white matter tract FA (r(276) = −0.18, p < 0.003). There was a significant indirect effect of NO2 between segregation and FA values (β = 0.08, 95% CI[0.01, 0.15]), and an indirect effect of PM2.5 between segregation and threat reactivity (β = −0.08, 95% CI[−0.14, −0.01]). There was no direct effect of segregation on hippocampal features. Pollutants and segregation were not associated with PTSD symptoms. In conclusion, residential segregation is associated with greater air pollution exposure, which is in turn associated with variability in hippocampal features among recent trauma survivors. Further research is needed to assess relationships between other environmental factors and trauma and stress-related disorders.
Funding
The investigators wish to thank the trauma survivors participating in the AURORA Study. Their time and effort during a challenging period of their lives make our efforts to improve recovery for future trauma survivors possible. The AURORA study was supported by NIMH under U01MH110925, the US Army MRMC, One Mind, and The Mayday Fund. The DISENTANGLE study is a continuation of AURORA’s work and is supported by the United States Army Medical Research Acquisition Activity (USAMRAA) under Contract No. W81XWH22C012. This project was supported by NIMH under F32MH134443 (Webb) and K01MH129828 (Harnett).
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The authors declare no competing interests.
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All procedures were approved by each site’s institutional review board, in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants, and participants were financially compensated for their time.
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• Dr. Harnett received funding from the National Institute of Mental Health (K01MH129828) and the Brain Behavior Research Foundation.
• Dr. Lauren Lebois reports unpaid membership on the Scientific Committee for the International Society for the Study of Trauma and Dissociation (ISSTD), grant support from the National Institute of Mental Health (K01 MH118467), the Julia Kasparian Fund for Neuroscience Research, and the Trauma Scholars Fund. Dr. Lebois also reports spousal intellectual property payments from Vanderbilt University for technology licensed to Acadia Pharmaceuticals and spousal private equity in Violet Therapeutics, unrelated to the present work. Neither ISSTD nor NIMH was involved in the analysis or preparation of this manuscript.
• Dr. Jovanovic receives support from the National Institute of Mental Health, R01 MH129495.
• Dr. Neylan has received research support from NIH, VA, and Rainwater Charitable Foundation, and consulting income from Otsuka Pharmaceuticals.
• In the last three years Dr. Clifford has received research funding from the NSF, NIH and LifeBell AI, and unrestricted donations from AliveCor Inc, Amazon Research, the Center for Discovery, the Gates Foundation, Google, the Gordon and Betty Moore Foundation, MathWorks, Microsoft Research, Nextsense Inc, One Mind Foundation, and the Rett Research Foundation. Dr Clifford has financial interest in AliveCor Inc and Nextsense Inc. He also is the CTO of MindChild Medical with significant stock. These relationships are unconnected to the current work.
• Dr. Germine receives funding from the National Institute of Mental Health (R01 MH121617) and is on the board of the Many Brains Project. Her family also has equity in Intelerad Medical Systems, Inc.
• Dr. Rauch reported serving as secretary of the Society of Biological Psychiatry; serving as a board member of Community Psychiatry and Mindpath Health; serving as a board member of National Association of Behavioral Healthcare; serving as secretary and a board member for the Anxiety and Depression Association of America; serving as a board member of the National Network of Depression Centers; receiving royalties from Oxford University Press, American Psychiatric Publishing Inc, and Springer Publishing; and receiving personal fees from the Society of Biological Psychiatry, Community Psychiatry and Mindpath Health, and National Association of Behavioral Healthcare outside the submitted work.
• Dr. Pascual is president elect of the Society for Clinical Care Medicine.
• Dr. Harte has no competing interest related to this work, though in the last three years he has received research funding from Arbor Medical Innovations, and consulting payments from Memorial Sloan Kettering Cancer Center, Indiana University, The Ohio State University, Wayne State University, and Dana Farber Cancer Institute.
• In the past 3 years, Dr. Kessler was a consultant for Cambridge Health Alliance, Canandaigua VA Medical Center, Child Mind Institute, Holmusk, Massachusetts General Hospital, Partners Healthcare, Inc., RallyPoint Networks, Inc., Sage Therapeutics and University of North Carolina. He has stock options in Cerebral Inc., Mirah, PYM (Prepare Your Mind), Roga Sciences and Verisense Health.
• Dr. Koenen has done paid consulting for the US Department of Justice and Covington and Burling, LLP. She receives royalties from Oxford University Press and Guilford Press.
• Dr. McLean has served as a consultant for Walter Reed Army Institute for Research, Arbor Medical Innovations, and BioXcel Therapeutics, Inc.
• Dr. Ressler has performed scientific consultation for Bioxcel, Bionomics, Acer, and Jazz Pharma; serves on Scientific Advisory Boards for Sage, Boehringer Ingelheim, Senseye, and the Brain Research Foundation, and he has received sponsored research support from Alto Neuroscience.
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Liang, S.S., Roeckner, A.R., Ely, T.D. et al. Associations between residential segregation, ambient air pollution, and hippocampal features in recent trauma survivors. Transl Psychiatry (2026). https://doi.org/10.1038/s41398-026-04083-6
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DOI: https://doi.org/10.1038/s41398-026-04083-6
