The gene signature may more closely reflect age in terms of health, according to the new study.
What is more, the signature - details of which are published in the journal Genome Biology - may ultimately help to change the way the health and age of individuals are assessed.
The researchers, led by James Timmons, professor of precision medicine at King's College, hope that the discovery will enable evaluation of individuals in terms of genetic condition, or "underlying biological age," rather than just chronological age.
The team also hopes their new development will make diagnosis possible well in advance of disease onset in order to boost preventive measures, with particular reference to Alzheimer's disease. Until now, there has been no way of testing underlying biological age.
The team set out to find a molecular profile that could predict a number of future conditions by creating a "healthy age gene score."
Data was gathered using blood samples; the presence of individual RNA molecules in blood cells reflects a range of influences on the body, since blood directly interacts with all organs.
To decide what represented healthy aging, samples were taken from healthy individuals aged 25 and 65, and a relationship was established between 150 classifier genes, chronological age and markers of lifestyle-associated disease. This was then collapsed into a single score: the healthy age gene score.
Having established this score, data was collected from a group of healthy 70-year-olds for comparison. This group was then followed up over a period of 20 years. The gene score within the group varied widely, despite all sharing the same birth year. Lifestyle markers for the group were also varied.
Low healthy gene score for Alzheimer's
Overall, there was found to be a significant discrepancy between the gene score, chronological age and actual health condition.
Furthermore, those with a high healthy gene score continued to maintain that score, as well as superior cognitive and renal function, over a period of 12 years.
In addition, those with Alzheimer's showed a lower healthy age gene score, indicating a link between Alzheimer's and the score.
Fast facts about Alzheimer's
- An estimated 5.1 million Americans may have Alzheimers
- Alzheimer's is the main cause of dementia in over 65s
- Alzheimer's is not a normal part of aging.
The authors propose evaluating individuals considered at risk of developing the disease during middle age, and offering entry into a preventive clinical trial.
It is anticipated that novel genomic diagnostics such as this will help predict future health care needs, guide targeted preventive measures and enable individualized treatment strategies for a number of diseases experienced in older age.
While it is hoped that the technique can be used to identify future diseases, such as Alzheimer's, the fact that one indicator might develop into a range of conditions over time is currently a limitation.
Nevertheless, with today's older population growing fast, current strategies for diagnosing and treating Alzheimer's are already difficult and expensive to maintain. This new strategy could help relieve the burden, if new data can be provided.
The perception not just of health care provision, but also of age, is changing. As Dr. Timmons points out: "We use birth year, or chronological age, to judge everything from insurance premiums to whether you get a medical procedure or not," while also accepting that "all 60-year-olds are not the same."
The UK's National Health Service (NHS) have called for "approaches to health and care that transcend traditional delivery boundaries" that will "transform diagnosis," while the US Food and Drug Administration (FDA) are working with various agencies to provide "the right patient with the right drug at the right dose at the right time." The healthy age gene score could be a step toward this goal.
In May, Medical News Today reported that $114 billion could be gained by using personalized medical interventions to prevent heart disease in the US.