Gwen Dewar, Ph.D.
April 14, 2014, 10:18 am
Family conflict, domestic upheavals, bad neighborhoods, bullying, depressed parents, harsh discipline, racism, medical crises – any of these can create serious, chronic stress for kids, the sort of stress that causes health problems and leaves its mark on the brain. But now there’s even more reason for concern:
Early life stress may genetically reprogram kids to age faster.
That’s the implication of a study by Colter Mitchell and his colleagues. The researchers were interested in telomeres, structures attached to the ends of our chromosomes that protect DNA from getting frayed or damaged. DNA damage causes many of the symptoms of aging, and telomeres are a bit like bumpers on an automobile. Just as a bigger bumper will do a better job keeping you safe in a collision, longer telomeres do a better job protecting your DNA.
But slowly, as the years go by, your telomeres shorten. And your apparent age – how you look and feel – is greatly influenced by the length of your telomeres. People who seem older than their chronological age have shorter-than-normal telomeres. By contrast, people who seem to defy the aging process are often blessed with longer telomeres. Protecting your DNA seems to be crucial for staying young.
What’s the secret, then, to preserving your telomeres? Past studies suggest that certain habits, like smoking, can shorten your telomeres. And research has linked chronic stress with telomere length in adults. But nobody had ever studied telomere length in children, not until Mitchell’s team did. So when they performed genetic testing on 40 African American, nine-year-old boys, they were venturing into new territory.
The boys came from two distinct backgrounds – one highly advantaged, the other highly disadvantaged. Advantaged kids came from affluent, stable families and had never been exposed to maternal depression or harsh parenting. Disadvantaged kids had the opposite experience – poverty, domestic instability, maternal depression and harsh parenting.
Sadly, the trouble facing disadvantaged boys went beyond the sum of their socioeconomic problems. They were also genetically worse off, with telomeres that were already 19% shorter than those of highly-advantaged kids.
Subsequent analysis showed that some factors were particularly important in determining a child’s telomere length. Having a mother with a high school degree (as opposed to a mom who hadn’t completed high school) was linked with 32% increase in telomere length. Being exposed to multiple changes in family structure, like having your parents break up, and then forming a new, “step” family, was linked with a 40% decline in telomere length.
Increases in family income (going from below the poverty line to being merely low-income) were linked with longer telomeres, but the effect was much smaller. So it maybe it wasn’t poverty per se that mattered so much, but instead the kind of family stress that often goes along with harsh, adverse environments.
If so, that’s consistent with the results of other research showing that kids growing up in poverty can avoid many of the associated health risks – if a secure, happy family life buffers them from toxic stress.
It’s too soon to reach any firm conclusions from the current study. The number of children tested was small, and this is just the beginning of research on telomere length in children. We need more information to better understand causation.
But Mitchell and his team note that certain kids – kids who carry “high risk” genes for negative emotions, depression, and thrill-seeking behavior – were especially sensitive to their environments. For them, a socially advantaged background had a big impact on telomere length.
So not every child is affected the same way by stress. But we shouldn’t kid ourselves. When it comes to adversity, there is a lot of inequality in the world. And it has serious, long-term consequences for children.