DNA Methylation Changes Correlated to War Trauma in Children and Adolescents

Background

Why researchers are looking to DNA to understand the long-term effects of ward on children’s health.

The number of displaced people worldwide has reached record levels, with millions of children fleeing conflict zones. These children often face not only immediate physical danger but also long-term psychological stress. While we already know that trauma can affect mental health, researchers are now exploring how extreme stress – like war – might change biology too. One of the ways trauma may leave a lasting impact is through a process called DNA methylation, a chemical change that affects how genes are turned on or off. This study looks at whether war leaves a biological imprint on the DNA of children who have lived through it.

What were the aims of this study?

Understanding whether war-related trauma in children affects their DNA

The researchers aimed to investigate whether war exposure changes DNA methylation in refugee children and adolescents. They also explored whether this trauma increases the rate of biological ageing and if previous trauma-linked DNA sites show the same changes in this population.

How was this study carried out?

Understanding how war affects biology through a large scale cross-sectional study

The study involved 1,507 Syrian refugee children and adolescents aged 6–19, living in tented settlements in Lebanon. Researchers collected saliva samples and interviewed both the children and their caregivers over two waves, one year apart. War exposure was assessed using a 25-item War Events Questionnaire, which asked about different types of traumatic events like bombardment, violence in the home, and personal harm. DNA methylation was measured at over 850,000 sites using a high-tech lab tool called the Illumina EPIC BeadChip. The team used statistical models to look for differences in methylation linked to war exposure. They also used a set of “epigenetic clocks” to estimate biological aging and tested whether trauma changed it. Lastly, they checked if previously identified trauma-related DNA sites matched any found in this study.

What were the key findings?

War exposure is linked to changes in DNA and may even slow biological ageing

The study found that children who had experienced war showed differences in DNA methylation at specific sites. For example, those exposed to violence in the home had increased methylation at a gene involved in fatty acid breakdown (ACBD5), while other types of violence led to decreased methylation in genes linked to brain cell communication (SCAMP5).

Interestingly, the total number of traumatic war events was also linked to changes in a gene (ADGRB2) related to mood in animal studies. However, only two of the 258 previously known trauma-linked DNA sites were found to overlap in this group, suggesting that war may affect biology differently than other types of trauma. The researchers also found that children exposed to war showed signs of slower biological aging, especially using the Horvath epigenetic clock—a surprising result, as stress is usually linked to faster aging. This was more noticeable in girls than boys, and might reflect delayed development rather than a protective effect.

What are the implications of this research?

A new insight into how trauma affects children and may help tailor global mental health support

This study highlights that war doesn’t just affect children emotionally or mentally—it can leave a physical trace on their biology too. This new finding has implications for how we understand the long-term impact of war on children’s health and development.

For global mental health professionals, these findings suggest that trauma-informed care should extend beyond psychological support to also address potential biological changes. The discovery that war exposure might slow biological aging raises important questions about how trauma affects children’s physical and cognitive development and what kinds of interventions might best support them.

Lastly, the limited overlap with previous trauma-linked DNA findings shows how important it is to study diverse populations, including refugees and people from non-Western backgrounds. Their experiences and biological responses may be different, and global health efforts must reflect that complexity

About the study team

The study team included Dr Demelza Smeeth (Queen Mary University of London, UK), Dr Simone Ecker (University College London), Dr Olga Chervova (University College London, Dr Fiona S. McEwen (Kings College London), Elie Karam (Institute for Development, Research, Advocacy and Applied Care), Dr Stephan Beck (University College London) and Professor Michael Pluess (University of Surrey, UK).