Science: Predicting Alzheimer’s Disease 10 Years Earlier

A new study conducted by Swedish scientists could open the path for easier and earlier screening for Alzheimer’s disease, with the possibility of detecting the incurable neurodegenerative disease up to a decade in advance.

arly detection of Alzheimer’s disease is critical for effective treatment. However, there are no reliable methods for such detection at present. The study, done by researchers from Sweden’s Karolinska Institutet and published April 12 in Alzheimer’s & Dementia—the journal of the Alzheimer’s Association—involves analyzing a type of glycan structure in the blood called bisected N-acetylglucosamine. This glycan structure is linked to the level of tau, a protein playing a key role in the development of severe dementia.

Glycans are sugar molecules found on the surface of proteins and are one of the major building blocks of life.

Identifying bisected N-acetylglucosamine can give doctors a pathway toward spotting individuals with a higher risk of Alzheimer’s. In fact, the study could open a way for a simple screening procedure capable of predicting the onset of Alzheimer’s 10 years in advance.

At the onset of Alzheimer’s, neurons in the brain die. Ensuring that treatment begins early when not many neurons have died is crucial to reversing Alzheimer’s.

In the study, researchers measured the blood glycan levels of participants. They found that individuals with matching levels of glycans and tau were more than twice as likely to develop Alzheimer’s-type dementia.

“We demonstrate in our study that blood levels of glycans are altered early during the development of the disease,” said Robin Zhou, first author of the study as well as a medical student and affiliated researcher at the Department of Neurobiology, Care Sciences and Society (NVS) at Karolinska Institutet, according to an April 12 press release.

“This could mean that we’ll be able to predict the risk of Alzheimer’s disease with only a blood test and a memory test.”

The research team had earlier found a link between tau protein and glycan levels among people affected by Alzheimer’s disease.

However, these tests were conducted on cerebrospinal fluid. Taking samples of cerebrospinal fluid is highly difficult. Meanwhile, brain imaging processes can be quite expensive. Markers in blood offer an easier and less expensive way to screen for the disease.

“We also show that a simple statistical model that take into account blood glycan and tau levels, the risk gene APOE4 and a memory test, can be used to predict Alzheimer’s disease to a reliability of 80 percent almost a decade before symptoms such as memory loss appear,” said co-author Sophia Schedin Weiss in the Karolinska Institutet announcement.

APOE4 is a gene that is linked to a higher risk of developing Alzheimer’s. The study looked at 233 participants of the Swedish National Study on Aging and Care in Stockholm (SNAC-K), with samples collected between 2001 and 2004.

The participants were monitored regularly for memory loss and the presence of dementia. The follow-ups continued for 17 years.

The lifetime risk of developing Alzheimer’s at the age of 45 is 1 in 5 for women. For men, the risk is 1 in 10.

Alzheimer’s disease and other forms of dementia are expected to cost the United States $345 billion in 2023—a number projected to get close to $1 trillion by 2050.