Children living in war-torn countries not only suffer from poor mental health outcomes, but war may cause adverse biological changes at the DNA level, which could have lifelong health impacts, according to a ground-breaking study from the University of Surrey. 

In the first study of its kind, the research team collected saliva samples from 1,507 Syrian refugee children, aged 6 to 19, living in informal settlements in Lebanon. They analysed DNA methylation (DNAm), an epigenetic process where chemical tags are added to DNA at various sites in the genome (the complete set of genes). These DNAm changes can turn genes on or off without changing the DNA code.

Questionnaires, completed by both the children and their caregivers, were used to measure exposure to the war-related events experienced by the child.