Impact of dioxin exposure on brain morphometry and social anxiety in men living in the most dioxin-contaminated area in Vietnam

Hoa Thi Vu; Thao Ngoc Pham; Muneko Nishijo; Takashi Yokawa; Tai Pham The; Tomoya Takiguchi; Yoshikazu Nishino; Hisao Nishijo

doi:10.1016/j.jpsychires.2023.09.002

Impact of dioxin exposure on brain morphometry and social anxiety in men living in the most dioxin-contaminated area in Vietnam

J Psychiatr Res. 2023 Oct:166:169-177. doi: 10.1016/j.jpsychires.2023.09.002. Epub 2023 Sep 22.

Authors

Hoa Thi Vu¹, Thao Ngoc Pham², Muneko Nishijo³, Takashi Yokawa⁴, Tai Pham The⁵, Tomoya Takiguchi⁶, Yoshikazu Nishino⁶, Hisao Nishijo⁷

Affiliations

¹ Department of Public Health, Kanazawa Medical University, Japan; Biomedical and Pharmaceutical Research Center, Vietnam Military Medical University, Hanoi, Viet Nam.
² Department of Functional Diagnosis, 103 Military Hospital, Vietnam Military Medical University, Hanoi, Viet Nam.
³ Department of Public Health, Kanazawa Medical University, Japan. Electronic address: ni-koei@kanazawa-med.ac.jp.
⁴ Kobe BMA Laboratory, BioView Inc., Japan.
⁵ Biomedical and Pharmaceutical Research Center, Vietnam Military Medical University, Hanoi, Viet Nam.
⁶ Department of Public Health, Kanazawa Medical University, Japan.
⁷ Faculty of Medicine, University of Toyama, Japan.

PMID: 37774667
DOI: 10.1016/j.jpsychires.2023.09.002

Abstract

Background: Previously, we reported that the global brain volume was significantly higher in men with estimated perinatal dioxin exposure in Vietnam. In this study, we aimed to clarify which brain lobes, consisting of several gyri, contributed to the increased global brain volume. We then analyzed associations between changes in brain volume and social anxiety symptoms to investigate the role of structural changes of the brain on social anxiety following perinatal dioxin exposure.

Methods: Thirty-three men living near the dioxin-contaminated Bien Hoa airbase, underwent MRI examination. The regional gray matter volumes were extracted using the SPM12 in a MATLAB environment, and compared between subgroups with and without perinatal dioxin exposure estimated from their maternal residency in Bien Hoa during pregnancy. The social anxiety questionnaire for adults (SAQ-A30) was used to assess social anxiety.

Results: In both hemispheres, higher gray matter volume in the frontal and temporal lobes, particularly in the superior frontal gyrus, superior temporal gyrus, and temporal pole were found in men with perinatal dioxin exposure. Superior temporal gyrus volume was significantly higher in men with perinatal exposure also after adjusting for reduction of its volume associated with increasing 1,2,3,7,8-PentaCDD levels in blood. Increased volume of these gyri, which showed higher volume in men with perinatal exposure, was associated with increased SAQ-A30 scores.

Conclusion: Perinatal dioxin exposure may increase the brain volume of gyri involved in social behavior, which was associated with increased social anxiety symptoms, suggesting functional effects accompanied the morphological effects of dioxin exposure.

Keywords: Brain regional volume; Dioxin; Neuroimaging analysis; Social anxiety; Vietnam.