Children in war-torn regions face not only severe mental health challenges but also potential biological changes at the DNA level that could have lifelong health consequences, according to a groundbreaking study by the University of Surrey.
In this first-of-its-kind research, the team analyzed saliva samples from 1,507 Syrian refugee children, aged 6 to 19, living in informal settlements in Lebanon. The study focused on DNA methylation (DNAm), an epigenetic process in which chemical tags are added to DNA, altering gene activity without changing the underlying genetic code. These changes can effectively switch genes on or off.
To assess the children’s exposure to war-related events, researchers used questionnaires completed by both the children and their caregivers.
In collaboration with University College London, the Institute for Development, Research, Advocacy and Applied Care (Lebanon), St. George’s University Lebanon, and a leading international NGO, the study found notable DNAm changes in children exposed to war. Some of these changes were linked to genes essential for neurotransmission (nerve cell communication) and intracellular transport (movement of materials within cells).
Interestingly, these DNA modifications appear unique to war-related trauma and are not typically associated with other forms of adversity, such as poverty or bullying. This finding suggests that war triggers distinct biological responses in the body.
The study was funded by the National Institutes of Health (NIH).
Professor Michael Pluess, lead author of the study from the School of Psychology at the University of Surrey, said:
“While it’s common knowledge that war has an adverse impact on the mental health of children, our study has found evidence of the biological mechanisms underlying this effect. We also found that war is linked to slower epigenetic ageing – which could mean that war could be impacting the development of children.
“All told, our study paints a clearer picture of the tragic cost of war, beyond the mental stress, for the many millions of children caught in the middle of it.”
This study is part of the BIOPATH initiative, a cohort study launched in 2017 and the first large-scale investigation of its kind among refugee children. BIOPATH aims to uncover how trauma influences mental health development, offering critical insights into the long-term effects of adversity.
The researchers also examined how the biological impact of war differs between boys and girls. They discovered that girls exposed to war events exhibited more pronounced DNA methylation (DNAm) changes than boys, particularly in genes associated with stress response and brain development. While trauma affected both genders, girls demonstrated a stronger biological response, suggesting greater vulnerability to the long-term molecular effects of war.
DNAm is a natural process in which small chemical groups, known as methyl groups, attach to specific sites on the DNA. These groups act as regulators, turning genes on or off or modulating their activity levels, without altering the DNA sequence itself.
While DNAm is essential for normal development and can be influenced by factors like diet and stress, extreme events such as war can induce significant changes. These changes may have lasting implications for physical and mental health. By studying DNAm, scientists aim to understand how traumatic experiences leave enduring biological imprints, shaping health outcomes over a lifetime.
The study has been published in JAMA Psychiatry.
