Children who are victims of bullying and violence have DNA wear-and-tear that is normally associated with ageing, a new study shows.
It found that violence-related stress in children affects telomeres - special DNA sequences found at the tips of chromosomes. Telomeres, which prevent DNA from unravelling, get shorter each time cells divide, which limits the number of times cells can divide.
Shorter telomeres have been linked to poorer survival and chronic diseases.
Previous research has shown that smoking, obesity, mental-health disorders and stress may accelerate the process of telomere loss. This suggests that telomere length may reflect a person's biological age as well as their chronological age.
How the study was done
In this study, Duke University researchers analysed data from a British study that tracked 1,100 families with twins from the twins' birth in the 1990s. DNA samples were collected from the children when they were five and 10 years old.
The Duke team found that children with a history of two or more kinds of violent exposures - such as domestic violence, frequent bullying or physical abuse by an adult - had significantly more telomere loss than other children.
The study was published in the journal Molecular Psychiatry.
"This is the first time it has been shown that our telomeres can shorten at a faster rate even at a really young age, while kids are still experiencing stress," Idan Shalev, a postdoctoral researcher in psychology and neuroscience at Duke University's Institute for Genome Sciences & Policy, said in a university news release.
The findings suggest that protecting children from harm may benefit their long-term health.
"An ounce of prevention is worth a pound of cure," study co-leader Terrie Moffitt, a professor of psychology and neuroscience, said in the news release. "Some of the billions of dollars spent on diseases of ageing such as diabetes, heart disease and dementia might be better invested in protecting children from harm."
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The U.S. National Institute on Aging has more about the biology of aging.
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