A new study seems to confirm what you might have suspected but thought was too silly to even say out loud: that two people, born at the exact same time, might have a different age, so to speak.

What’s The Test All About?

A team of researchers based at King’s College, London have developed a diagnostic that looks at the pattern of RNA expressions in tissues and uses that as a marker for health; in effect, it tests whether a patient’s tissue are (biologically speaking) older or younger than their (chronological) age.

The researchers developed this test by carefully going over thousands of RNA expressions in muscle tissue from healthy (but sedentary) 25 and 65 year olds. After comparing the two groups, the researchers were able to identify a core of 150 biomarkers that could be used as a baseline of sorts for healthy aging.

“Our approach was novel because we first sought to define a set of genes associated with healthy ageing in ‘normal’ 65-year-old subjects, rather than gene expression associated with disease or extreme longevity,” reports the team in the journal Genome Biology.

So What Did They Find Out?

“Our discovery provides the first robust molecular ‘signature’ of biological age in humans and should be able to transform the way that age is used to make medical decisions. This includes identifying those more likely to be at risk of Alzheimer’s, as catching those at early risk is key to evaluating potential treatments,” said Professor John Timmons, lead researcher of the study.

“There was a very strong difference between people with mild cognitive impairment and [healthy people], so it seems as if it could be developed into a test, particularly when combined with relevant clinical variables. However most likely it represents a way to spot ‘at risk’ people and guide them toward clinical trials for prevention,” he said.

Age 40: How Will This Be Of Any Use?

Well, first there is its utility in managing mental illnesses, particularly dementia and Alzheimer’s Disease.

The test can gauge which of the subjects are going to get Alzheimer’s Disease and dementia.

“The shift in population demographics in the coming decades will mean that more than 1.2 billion people will be aged 65 years or older worldwide,” write the researchers, adding that 7% of them will have dementia, and two-thirds of this group will have Alzheimer’s disease.

The problem with Alzheimer’s is that by the time the patient starts displaying symptoms of the disease, it is too late. The early detection that this test has facilitated just might take the disease out of existence.

Then, there is the issue of organ transplants. The differentiated response of patients of the same age to an transplanted organ is caused by a variety of factors, but biological age wasn’t ever taken into account. It will now. And the age of the donor will also cast a new light on the issue.

“We use birth year, or chronological age, to judge everything from insurance premiums to whether you get a medical procedure or not. Most people accept that all 60-year-olds are not the same, but there has been no reliable test for underlying biological age,” Professor Timmons said.