Last week, a report published in Nature Medicine offered the blockbuster news that, in 9 of 10 cases, a blood test can identify people in their 70s who are likely to develop Alzheimer’s disease with a couple of years.
The news carries a mixed message.
As explained on NPR.org, the test is much easier than the painful, invasive and/or expensive tests now available to diagnose a disease for which there is no cure, and very little treatment. The new test might be able to predict better who will get Alzheimer’s, which might spur the development of a treatment to slow to stop it. But because we still can’t do that, people considering the test must be prepared to get results that, as the story put it, “could be life-altering.”
The research team led by Dr. Howard Federoff, professor of neurology at Georgetown University, took blood samples from 525 people 70 and older and monitored them to see who developed Alzheimer’s in the next five years, and if there was a difference in the blood of people who developed Alzheimer’s versus those who remained “cognitively normal.”
And after analyzing more than 4,000 potential “biomarkers,” Federoff reported that “We discovered that 10 blood lipids (fats) predicted whether someone would go on to develop cognitive impairment or Alzheimer’s.”
Like all initial studies, the results of this one must be confirmed, and the protocol must be repeated with people of different ages and racial groups. But the possibility has been raised that in the not too distant future, many more people will know their risk of Alzheimer’s.
That’s good, because if you know your risk you can plan your future better – where you live, how you allocate resources, what information you share with loved ones…
But it could be bad, explained Dr. Jason Karlawish, a professor of medicine, medical ethics and health policy at the University of Pennsylvania who was interviewed by NPR. That’s because people who know they have the Alzheimer’s gene tend to rate their own memories as worse than people who have the gene but don’t know it. So knowledge, in this case, might artificially affect performance on memory tests.
A bigger concern about Alzheimer’s testing might be the question of perception and identity. As Karlawish said, “How will other people interact with you if they learn that you have this information? And how will you think about your own brain and your … sense of self?”
The stigma and fear that now surround Alzheimer’s might evolve positively with our understanding and our ability to diagnose it in advance. But right now, the disease is seen largely as a zero-sum situation: “[E]ither you have Alzheimer’s disease dementia or you’re normal, you don’t have it,” Karlawish said.
But that perception isn’t helpful, and probably is inaccurate. Karlawish said Alzheimer’s is like heart disease; it starts with biological changes that occur long before symptoms appear. And there is no bright line separating healthy people from those in early stages of the disease.
Whatever your experience might be, we repeat our caution to beware of the many scams out there promising to diagnose Alzheimer’s – see our blog, “Online Alzheimer’s Tests Are a Waste of Time and Electrons.”