‘You Can Catch Alzheimer’s’: Really?
Sept. 11, 2015 — People in the United Kingdom and around the world woke up to some brain-shrinking headlines Thursday morning.
“You Can Catch Alzheimer’s,” said the front page of London’s Daily Mirror.
“Alzheimer’s Disease May Be Caught Through Medical Accidents,” was the headline on the Telegraph’s story.
The coverage was based on a study published in the journal Nature. The study authors suggest it might be possible — under extraordinary circumstances — for the same kinds of plaques seen in the brains of people with Alzheimer’s to be passed from one person to another.
We checked with the experts. Should you be worried about catching Alzheimer’s disease?
“No,” says David Knopman, MD, a neurologist at the Mayo Clinic in Rochester, MN. “And then I would repeat, ‘No.’ And again, ‘No,’” he says. Knopman says he was “appalled” to see the claims made about the study.
Let’s take a look at the science.
The researchers behind the study are experts in prion diseases. Prions are responsible for a number of degenerative brain diseases, including Creutzfeldt-Jakob disease (CJD), also known as “mad cow” disease when it occurs in cows. It causes rapid memory loss, behavioral changes, a loss of vision and muscle coordination, and ultimately, death.
Prions can damage other proteins just by touching them. They can pass from one person to another through biologic products like blood and human tissue transplants. Before 1985, growth hormone injections used to treat short children were made by extracting the hormone from human tissue. In some cases, those batches of growth hormone were contaminated with prions, and some who received those injections have gone on to get the disease decades later.
The subjects in the new study were eight people between the ages of 36 and 51 who had all been treated with this contaminated growth hormone and later died from CJD.
During autopsies, doctors noticed something interesting. In addition to the tell-tale prion damage, four of the eight people also had a significant build-up of beta amyloid proteins. Sticky beta-amyloid plaques are also seen in the brains of people with Alzheimer’s. Doctors use the build-up of beta amyloid along with other brain and thinking changes to help diagnose people with the disease.