Researchers from Brigham and Women's Hospital (BWH) and Harvard Medical School in Boston, USA, write about their findings in a paper published 11 July in the open access journal PLoS ONE. They suggest phobic anxiety is a possible risk factor for premature aging, with shortened telomeres as a plausible mechanism.
TelomeresTelomeres, considered markers of biological or cellular aging, are bits of DNA protein at the ends of chromosomes that protect them from deteriorating; so when cells divide, their genetic information is preserved. (Think of the protective plastic sleeves on the ends of shoelaces that stop them from fraying).
Shortened telomeres have been linked to increased risk of cancer, heart disease, dementia and premature death.
Blood Samples from Over 5,200 WomenFor the cross-sectional study, the researchers used blood samples from 5,243 women aged between 42 and 69 who were taking part in the Nurses' Health Study, one of the largest and longest running investigations of factors that influence women's health that started collecting data in 1976.
From the blood samples they were able to determine telomere length of blood cells. As participants of the Nurses' Health Study, at the time of giving the blood samples, the women had also filled in validated questionnaires that included questions about phobic symptoms, so the researchers were able to correlate these to telomere length.
The results showed that having a high level of phobic anxiety was significantly linked to having shorter telomeres.
Shorter Telomeres As Plausible Mechanism for Premature AgingThe difference in telomere length between women with the highest levels of phobic anxiety and women with no symptoms was equivalent to an additional age of six years, say the researchers.
First author Olivia Okereke, is from the Department of Psychiatry at BWH. She told the press:
"Many people wonder about whether - and how - stress can make us age faster."
"So, this study is notable for showing a connection between a common form of psychological stress - phobic anxiety- and a plausible mechanism for premature aging," she added.
Further Proof NeededHowever, Okereke is tentative about the findings. The study was not designed to establish cause and effect: as a cross-sectional study (one that finds links between measurements done at the same point in time), the most it can do is point out links and say how strong they are.
These findings do not prove "which problem came first - the anxiety or shorter telomeres", said Okereke.
But they are strong enough to suggest this is worth investigating further, using prospective studies that examine measures taken over a period of time and provide a more reliable estimate of what causes what.
A Harvard Medical School Shore Fellowship award and grants from the National Institutes of Health helped fund the study.
Written by Catharine Paddock PhD