Epigenetic signatures of war and conflict-related trauma - a study of refugee families in Africa
Biological Psychology and Cognitive Neuroscience
Final Report Abstract
The study investigated potential associations between war-related trauma exposure or PTSD symptom severity and altered DNAm profiles in refugee families using EWAS and WGCNA and did not identify any significant results controlling for biological and technical confounders and multiple testing. Several limitations of our study might account for the null-findings. First, epigenome-wide DNAm levels were assessed from peripheral buccal epithelia cells, and any potential influence of war-related trauma on the epigenome might not be reflected in buccal epithelium. Second, the buccal swabs were taken from Burundian refugees living in refugee camps where oral hygiene was poor. Potential bacterial contamination of the human DNA in the buccal samples was addressed by only including CpGs with high quality based on quality control during preprocessing. Third, with the available sample size, the study was not adequately powered to detect small effects, so that unidentified false-negative results cannot be ruled out in our study. Forth, due to the power issue, it was not possible to address interaction effects between the predictor of interests and the participants’ sex. Future studies with larger sample size should account for such interaction effects to be able to identify potential significant effects on DNAm profiles. A strength of the study was that the epigenome-wide DNAm was regressed on the actual trauma load as well as PTSD symptom severity in contrast to previously reported EWAS using a case-control approach with participants with and without PTSD diagnosis as indirect indicator of trauma exposure. In order to understand the dynamics in DNAm profiles, linearly regressing the outcome on continuous predictors generally gives detailed insight into the form of association that is generally not addressable using group comparison. Future EWAS with larger sample size of children and caregivers could give insight into multilevel effects between family members. To conclude, this study contributes to the generally understudied population of African individuals since other ethnic populations appear to be overrepresented in PTSD-EWAS. Overall, we hope to contribute to the understanding of the psychological and biological underpinnings of behavioral vulnerability and resilience to traumatic stress and PTSD risk. This could help to develop preventive strategies and therapeutic interventions for PTSD after war experiences.
Publications
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No association between war-related trauma or PTSD symptom severity and epigenome-wide DNA methylation in Burundian refugees. European Journal of Psychotraumatology, 14(2).
Mattonet, Katharina; Scharpf, Florian; Block, Katrin; Kumsta, Robert & Hecker, Tobias
