A simple blood test that a researcher calls a "game changer" may be able to accurately predict whether older adults will develop dementia.
The experimental test, developed by researchers at six universities, was 90 percent accurate at predicting whether adults age 70 and older would develop either mild cognitive impairment or Alzheimer's within two to three years. The study was published online Sunday in the journal Nature Medicine.
The test measures the levels of 10 lipids, or fats, in the bloodstream. Low levels signal a person is likely to suffer cognitive impairment, said researchers with Georgetown University, one of the medical centers involved in the research.
Lead researcher Howard Federoff, M.D., Executive Vice President for Health Sciences at Georgetown, told NPR the test would be an easy way for older people to determine their risk of dementia, and would be a "game changer" if researchers can find a drug to slow down or cure the disease.
The idea, he said, is to identify those at risk early, when treatment might be more effective at protecting the brain, rather than waiting until the damage is already underway.
The new study involved 525 healthy adults age 70 and over who were given blood tests annually for five years. During those years, 74 developed mild cognitive impairment or Alzheimer's. Researchers then compared their blood with those who remained mentally healthy to see what was different. What they found was the dementia group had lower levels of a group of 10 lipids than did the healthy group.
To measure the accuracy of these lipids at predicting dementia, researchers then tested a second group of 40 people. They even added a genetic test that looks for a mutant gene linked to Alzheimer's. The blood test predicted dementia with better accuracy than the gene test alone, researchers reported.
A simple, accurate way to identify those at risk for dementia - along with an effective treatment to do something about the disease - is even more urgent today as the population ages. Alzheimer's currently affects about 5 million Americans, and a recent study estimates that it kills more than 500,000 a year, six times more than previously thought.
Although this blood test is still experimental and not ready to use on patients, it's an important step toward finding "a relatively inexpensive and noninvasive biomarker to allow us to screen large groups of people," Ronald Petersen, M.D., director of the Mayo Clinic's Alzheimer's Disease Research Center, told NBC News.
A blood test would certainly be easier to administer than current tests for identifying early Alzheimer's, agreed Maria Carrillo, vice president of medical and scientific relations at the Alzheimer's Association, but further trials are needed "in larger and more diverse populations," she told HealthDay.
Despite the test's seemingly dramatic results, the study found only an association between low levels of the 10 fats and developing dementia, not proof of cause and effect.
Even Federoff acknowledged that researchers don't know why all 10 lipids are lower in individuals who are predisposed to cognitive impairment. "We can't directly link this to our current understanding" of Alzheimer's disease, he said.
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