A blood test may now show how healthy people are aging and can also predict the onset of diseases like Alzheimer's, says a new study.
A set of genes are responsible for promoting healthy aging in 65-year-olds. Researchers at Kings college London said that the test will help doctors decide which middle-aged subjects could be offered preventative therapies before the first symptoms of dementia begin to appear.
It is also the first and practical accurate test to determine the rate at which individuals are aging. The working of the genes can be predicted using a 'healthy age gene score'. The lower the score the more likely disease is present or likely to develop.
"Most people accept that all 60 year olds are not the same, but there has been no reliable test for underlying 'biological age'. 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," said lead author James Timmons, from King's College London.
"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. This also provides strong evidence that dementia in humans could be called a type of 'accelerated aging," he added.
The seven-year collaborative study at King's College London, Karolinska Institutet in Sweden and Duke University in the USA, used a process called RNA-profiling to measure and compare gene expression in thousands of human tissue samples.
They compared tissue samples from 25-year-olds to that of 65-years-olds and identified a pattern of activation in 150 genes which was required to be in place for healthy aging. They found drastic differences in the age scores of people in different age groups particularly between a year. Therefore they suggested that biological age differs considerably from chronological age.
People with the worst 'health age gene score' were far more likely to suffer from mental decline and poor health such as loss of renal function. In particular, they demonstrated that patients diagnosed with Alzheimer's Disease had much lower scores, suggesting significant association with the disease.
Dr. Neha Issar-Brown, program manager for population health sciences at the Medical Research Council, which funded the research added, "Whilst it is natural for our bodies and brains to slow down as we age, premature aging and the more severe loss of physical and cognitive function can have devastating consequences for the individual and their families, as well as impact more widely upon society and the economy. This new test holds great potential as with further research, it may help improve the development and evaluation of treatments that prolong good health in older age."
Dr Doug Brown, Director of Research at Alzheimer's Society said, "With further development this research could help in our quest to find new treatments for the condition, by identifying people who are more likely to develop Alzheimer's disease so that they can participate in clinical trials."