You take your vitamins, do your Sudoku, and get your cardio in — but sometimes, it’s the old roll of the genetic dice that brings you a host of diseases associated with aging and cognitive decline.
However, a team of scientists recently discovered a way to determine if the aging processes of your body and brain are normal or whether there are underlying abnormalities that signal an increased risk for diseases such as Alzheimer’s.
A simple blood test can be used to analyze a unique combination of 150 genes associated with what James Timmons and a team of researchers refer to as “healthy aging.”
“This is the first blood test of its kind that has shown that the same set of molecules are regulated in both the blood and the brain regions associated with dementia, and it can help contribute to a dementia diagnosis,” Timmons, a professor of precision medicine at King’s College London, said in a press release.
Old but Good Genes
While previous research looked for genes specific to certain diseases, such as Alzheimer’s, diabetes, or cancer, this study sought to identify genes associated with normal, healthy aging.
Researchers analyzed the RNA of a group of sedentary but otherwise healthy 65-year-old subjects to find the 150-gene “gene signature” associated with healthy brain, muscle, and skin tissue.
This signature was then compared to the RNA of healthy 70-year-olds, who were given a “gene score” and followed over a 20-year period.
Participants with higher gene scores demonstrated better cognitive function, longer lives, and better kidney function (a good predictor of overall long-term health).
Using the genes identified with healthy aging, researchers can look for aberrations or lower gene scores. These low scores could be used as a sort of warning flag for the risk of developing cognitive impairment and possibly other diseases associated with aging.
“Our test is not a test for cancer,” Timmons clarified in an e-mail to Healthline. “However, if you have a poor age score you might wish to be tested for specific cancers at a younger age. For example, get tested at 40 rather than wait until 50.”
Blood Tests Are the New Brain Scans
Researchers also found that the gene scores of people with Alzheimer’s disease were much lower than those of healthy older people.
The study was careful to control for diseases such as diabetes and vascular disease, which are often associated with aging but are brought on by a much more complex combination of lifestyle and genetics.
“We did not want to find something that was a correlate of lifestyle because that is not 'aging,'” Timmons explained. “We can already assess lifestyle risk factors, and it was important to discover a new risk factor. … We need to know we are not being fooled by other diseases that exist in older people.”
Lower gene scores were not associated with blood samples from those with diabetes and vascular disease, but even in these samples, the test was able to pinpoint cognitive impairment.
This finding suggests that an abnormally aging brain could still be detected in an individual with other health problems.
How Old Are You Really?
“One of the most striking parts of the project was that we could measure the 150 RNAs in the human brain region most linked to Alzheimer’s disease and dementia, and show that in healthy humans the 'gene signature' was switched on exactly as we see it in muscle,” Timmons said. “To link that to the measure of the same genes in blood strongly argued that this was a systemic response to aging.”
In short, the blood test gives a picture of the age of many different types of tissue — a sort of overall analysis of an individual’s biological age.
In the portion of the experiment that followed 70-year-old men, for example, the test found a four-fold range in the gene score. While the men were less than a year apart chronologically, their biological ages were vastly different.
While the test is not diagnostic of Alzheimer’s disease or cognitive impairment, it’s a promising development for a society that’s rapidly aging.
More than 5 million Americans currently have Alzheimer’s disease, and the estimated cost of dementia-related expenses for 2015 is $226 billion.
Alzheimer’s can’t be prevented or cured, but some newer treatments can slow the symptoms of the disease. Early diagnosis is crucial to preserve normal functioning for as long as possible.
With the healthy aging test, a low gene score could find individuals at risk for dementia. Further research could tell us more about when and how an individual moves from the at-risk category into the diseased category.
But, perhaps more crucially, a low gene score could be used to enroll an individual into a clinical trial that seeks to prevent or slow the progression of disease — something that could change that individual’s life significantly.
“Currently there are no genetic tests [for Alzheimer’s disease], and screening using brain images only works when the disease is very established,” Timmons said. “So what we need is a simple blood screen for people around 60 years old that tells us their future risk. … We think our age score can help with both these aims. It does not diagnose Alzheimer’s, but can be a powerful tool to help Alzheimer’s research.”