Psychological stress may be enough to age a woman鈥檚 chromosomes by 10 years, a new study suggests.
The link between stress, ageing and health at the cellular level is unclear, but a team led by Elissa Epel of the University of California at San Francisco, US, has now looked at the effect of stress on the cell.
A piece of DNA called a telomere caps the ends of each chromosome, protecting those ends and promoting genetic stability. Each time a cell divides, the telomeres shorten so that daughter cells have slightly shorter telomeres than their parents.
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But in young people, an enzyme called telomerase corrects the process, regenerating the ends. However, in older people the telomeres shorten significantly and eventually their replication stops altogether.
Chronically ill children
To study the effect of stress on the cell, Epel and her colleagues looked at the chromosomes in the white blood cells of 58 mothers, two-thirds of whom had chronically ill children. The other women had healthy children so may be expected to suffer less stress.
Perhaps surprisingly, there was no difference found in the telomere length of the two groups, but women in both groups who reported the most stress did have the shortest telomeres. And the effect was so large that it represented nine to 17 years鈥� worth of cell ageing.
Epel says she is not surprised. 鈥淚 believe that how we perceive the world can matter more than our objective reality,鈥� she says. 鈥淚f we feel stress it needs to be taken seriously because it may be embodied at the cellular level.鈥�
Those that had been caring for a sick child for longest also had short telomeres, regardless of their perceived stress. 鈥淯nfortunately, the longer the women were caregiving, the worse off they were,鈥� says Epel.
Further research must be done, says Epel, to confirm the results of the small study, which did not control for lifestyle, social status or environmental exposure. 鈥淲hether you are a caregiver or not, stress is a red flag,鈥� she notes.
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0407162101)