It is said that time waits for no man, but biologically speaking some people are barely aging at all while others are speeding through their lives at the rate of three years every 12 months, scientists have found.
For the first time researchers have developed a test which reveals not only biological age but how fast people are growing old.
And the results are startling. In a group of 38-year-olds, the scientists discovered that some had the same physiology as a 30-year-old while others were closer to 60.
The researchers from a range of institutions including Kings College London and Duke University in the US, believe it could explain why some people look far older than their years, while others appear to hardly age from year to year.
“We are now at a point where we can quantify biological aging in young people, “ said Dr Andrea Danese, Senior Lecturer in Developmental Psychobiology and Psychiatry at Kings College London.
“And for the first time we can see how fast they are aging. The people who had the oldest biological age were growing old the fastest.
“If we know that we can think about changing diets or making lifestyle changes when it is early enough to do something about it.
“With these tests we could detect premature aging before young people being to develop heart disease, diabetes or dementia so we could treat them.”
To discover what biological markers in the body could show the rate of growing old, the scientists have been following more than 1,000 people who were born in 1972-73.
Just as hair goes grey and wrinkles appear, all parts of the body slowly deteriorate with age, and that can be measured to work out a person’s true biological age. Someone who has never smoked, exercised regularly and eaten a healthy diet may have protected themselves against much of the ravages of time, whereas a person who lives an unhealthy lifestyle will speed up the process.
The researchers looked at 18 indicators of health including kidney and liver function, blood pressure, cholesterol levels, and the length of telomeres – the protective caps at the end of chromosomes which prevent DNA damage.
They carried out the tests when participants were aged 26, 32 and 38 to see how they were changing over time. Although most people were around their real age, and were aging at a rate of 12 months in one year, some were aging as fast as three years per chronological year while others were not aging at all.
Photographs of the volunteers were also handed out to students at Duke University who were asked to assess their age. Those who were biologically older invariably appeared older to the students.
The scientists claim that most of the difference in aging rates are down to environmental factors rather than genes, and so could be altered. It is though that just 20% of differences in aging is genetic.
“There is a great deal of environmental influence,” said lead author Dan Belsky, assistant professor of geriatrics at Duke University’s Centre for Aging.
“As we get older our risk grows for all kinds of different diseases. To prevent multiple diseases simultaneously ageing itself has to be the target. Otherwise it’s a game of whack-a-mole.”
The researchers are hopeful that in future doctors would be able to test people when they are in their 30s to determine how fast they are aging so that they could offer health advice or medication.
Professor Terrie Moffitt, of Duke University added: “It is indeed likely that individual patients will be able to get a number for their own biological age, by asking their family doctor. Most of the 18 biomarkers we used in our research are used routinely in clinical practice already, nothing mysterious.
People can already go to the internet to calculate their “heart age”, entering their blood pressure, height, weight, and whether or not they smoke, and so forth. But our measure of the pace of aging is a bit different, as it is based on aspects of organ function that are “hidden” inside young people who still feel and look healthy; it does not rely on observable behaviours such as smoking.
One goal we need to meet next is to determine which are the fewest biomarkers needed to accurately estimate a person’s biological age."
The research was published in the journal the Proceedings of the National Academy of Sciences.