But time seems to stand still for others, with some appearing not to have aged at all. Based on their scores on these measures, researchers calculated a biological age for each volunteer.
“And by 2050, the world population aged 80 years and over will approach 400 million people, so we are facing an enormous global burden of disease and disability unless we can extend healthy lifespans”.
Expert created 18 measures to determine how quickly a person is ageing, including tests of kidney, liver, lung and immune system function as well as assessments of metabolism, cholesterol, heart health, lung function, and the length of telomeres – protective caps on the ends of chromosomes.
Lead scientist Dr Dan Belsky, from Duke University Center for Ageing, said: “We set out to measure ageing in these relatively young people”.
The study authors say their findings pave the way for future tests that may be easier and cheaper to implement, so that people can find out how fast they are ageing in their 20s, when they might be able to do something about it and possibly prevent age-related diseases.
“As we get older, our risk grows for all kinds of different diseases”, he said.
“This is the first step to detect factors that influence the rate of ageing… very early prevention [of diseases] may be one of the things we will be able to measure better”. “Otherwise it’s a game of whack-a-mole”. Of the original group, 30 had died by the age of 38 due to serious diseases such as cancer, or by accidents, suicides and drug overdoses.
They carried out the tests when participants were aged 26, 32 and 38 to see how they were changing over time.
After drawing a slope for each variable, the team added the18 slopes for each member to determine that individual’s hidden pace of aging while they were still young on the outside.
For most participants, chronological age and biological age kept at roughly the same pace.
Most participants clustered around an aging rate of one year per year, but others were found to be aging as fast as three years per chronological year. “A biological age of 40, for example, meant that person was aging at a rate of 1.2 years per year over the 12 years the study examined”, he said.
The researchers drew on data gathered on 871 people enrolled in the Dunedin study, a major investigation that has tracked the health and broader lives of around 1000 New Zealanders born in 1972 or 1973 in the town of Dunedin, New Zealand.
In addition, biologically older individuals reported more difficulty undertaking physical tasks such as walking up stairs. Again, the participants who were biologically older on the inside also appeared older to the college students.
As a fulltime scientist, the 26-year-old says she can appreciate the complex challenges researchers face in trying to slow rates of ageing globally – and why it’s so crucial they tackle the issue.
But the good news is that the ageing process is not set in stone – studies of twins have shown that only about 20% of ageing can be attributed to genes.
“That gives us some hope that medicine might be able to slow aging and give people more healthy active years”, said senior author Terrie Moffitt, professor of psychology and neuroscience at Duke University.