How Old Is Your Body? Blood Test Can Tell You, and Predict Alzheimer's Too

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A simple blood test could tell us, one day, how old are bodies are functionally - and how likely we are to come down with age-related conditions, inclufing Alzheimer's. (Illustration)Credit: Limor Edrey

You may be 60 years old but feel, say, 45. How old are you? It may not convince your insurer, but a bunch of scientists has come up with a blood test that can analyze how old your body really is, not in chronological age, but biologically. Moreover, their discovery could lead to earlier and therefore more useful treatment for various aging-related illnesses.

Our genetic material is DNA, which is translated into RNA, which is in turn translated into proteins. By analyzing RNA of healthy 70-year olds, the scientists developed a "signature", of 150 RNA transcripts that indicates whether the person is aging healthily, or not – and can be a diagnostic of future health.

Put otherwise, they created a checklist of RNA molecules (taken from different parts of the body, including muscles and brain) that puts out a "healthy age gene score". Applying it to 70-year old test subjects that were then followed led to the conclusion that a higher score was associated with better health – and cognitive function - in men and women.

The RNA signature was found to be a reliable predictor for risk of age-related diseases well before any symptoms actually appear, the large multinational team reports in Genome Biology.

Though the point was general aging, not one particular disease, the team notes that patients ultimately diagnosed with Alzheimer’s had a lower score.

"This also provides strong evidence" – if not proof – "that dementia in humans could be called a type of ‘accelerated ageing’ or ‘failure to activate the healthy ageing program’," said lead author James Timmons of King’s College London.

Your insurer knows

"We use birth year, or chronological age, to judge everything from insurance premiums to whether you get a medical procedure or not," Timmons points out - yet although born in the same year, by their 60s and 70s, people are very different. But there had been no way to quantify their biological difference in aging – until now.

Timmons elaborates: "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," he explains.

Indeed, while a cure for Alzheimer's – that would improve the patients' condition, as opposed to stabilizing it – remains lacking, early detection of that and other conditions can be helpful to minimizing its effect. (Though there are promising signs from a drug under development at Biogen). But whether we really want our insurer to get the results of that blood test is another matter entirely.