Children who experience violence or trauma seem to age faster, going through puberty earlier and showing greater signs of ageing in their cells, researchers have found.
They say the findings add to a growing body of work that suggests early adversity can become “biologically embedded” with the potential for adverse health effects later in life.
“There are also clear practical implications for these findings,” said Dr Katie McLaughlin, co-author of the research at Harvard University. Screening for adversity may be warranted in children who have early puberty to help identify those who might be at risk of early onset of physical and mental health problems, she said.
Writing in the Psychological Bulletin, McLaughlin and her colleagues describe how they analysed 54 studies looking at the impact of two forms of adversity on the onset of puberty and ageing markers in cells.
In both cases, the result reveal children who had experienced violence or trauma, but not deprivation, showed accelerated ageing compared with those who had not.
Figures varied across the different studies, but repeated exposure to violence appears to be linked to girls experiencing menarche up to several months earlier than their peers. Although a small effect the team say it may be important, noting that earlier puberty has been linked to mental and physical health problems later.
In the case of cellular ageing – as measured by the shortening of telomeres, the caps on the end of chromosomes, and the accumulation of methyl groups on DNA – the team say children who experienced violence or trauma appeared to be months or even years older than they really were.
“We know [these measures] are very powerful predictors of health outcomes and even mortality later in life,” said McLaughlin. Studies in adults suggest faster biological ageing at the cellular level is associated with increased risk of conditions from cancer to cardiovascular disease.
The team also examined a further 25 studies on the impact of childhood adversity on the thinning of the cortex, the outer layer of the brain, which occurs with age and is linked to an increase in efficiency in processing.
“What we see is that growing up in a dangerous environment accelerates that process for regions of the brain that are processing social and emotional information and helping us to identify and respond to threat,” said McLaughlin. That may be beneficial in the short term, but other work suggests such changes could be linked to an increased risk of mental health problems, she said.
Accelerated thinning was also seen in children who experienced deprivation, but in different regions of the brain, including those linked with memory and decision making.
For all markers of ageing, the effects of childhood adversity appeared to scale with the magnitude or severity of the experience. The team note that only small number of studies were explored for each measure of ageing, and that the role of genetic heritability in the findings requires further scrutiny.
McLaughlin said, however, that it made sense that different forms of adversity had different impacts. “The types of adaptations that are likely to help children adapt to a dangerous environment are very different than those that might be needed in an environment that is deprived,” she said.
Andrea Danese, a professor of child and adolescent psychiatry at Kings College London, welcomed the research.. “The findings suggest that a more detailed assessment of children’s experiences could inform about their underlying risk for biological ageing,” he said.
“In turn, this could guide further research to understand why age-related conditions, such as cardiovascular disorders or some forms of diabetes, are more prevalent in individuals who have experienced childhood adversity.”…
He also said, however, that the differences were small, meaning they could not be used to target approaches to individual children.Nor was it clear why threat experiences such as violence are linked to faster ageing.
“Threat experiences are associated with several characteristics of the child, the family and the community, which could account for the observed differences and should be better understood,” he said. “This will enable us to strengthen causal inference and inform the development of effective interventions to alleviate the health burden associated with adverse childhood experiences.”