Scientists have created a new tool that estimates a person’s risk of developing memory and thinking problems linked to Alzheimer’s disease years before symptoms appear.
Alzheimer’s is marked by the aggregation of two key proteins in the brain – amyloid, which forms plaques, and tau, which forms tangles.
Studies have shown that people with a variant of the APOE gene have a higher lifetime risk of developing Alzheimer’s.
Drugs currently prescribed for mild forms of the condition remove amyloid clumps from the brain to slow the rate of disease, but not stop its progression.
To ensure even these drugs are given early, researchers are looking for ways to detect signs well before the first symptoms develop and see if people at the greatest risk can be identified.
The new tool, detailed in a recent study, is a prediction model that combines factors like age, sex and genetic risk associated with APOE and brain amyloid levels seen on PET X-ray scans to calculate an individual’s likelihood of developing dementia within 10 years.
Researchers say the amyloid protein levels detected on PET scans are the most crucial factor.
“This kind of risk estimate could eventually help people and their doctors decide when to begin therapy or make lifestyle changes that may delay the onset of symptoms,” Dr Ronald Petersen from Mayo Clinic in the US, one author of the study published in The Lancet Neurology, said. “It’s similar to how cholesterol levels help predict heart attack risk.”
The new study builds on decades of data from the Mayo Clinic Study of Ageing, one of the world’s most comprehensive studies that tracks thousands of people over time.
Researchers assessed data from 5,858 participants in the latest study, following them using medical records and ensuring near-complete information about who developed cognitive decline or dementia.
“This gives us a uniquely accurate picture of how Alzheimer’s unfolds in the community,” Terry Therneau, another author of the study, said.
“We found that the incidence rate of dementia was two times greater among the people who dropped out of the study than those who continued to participate.”
Scientists hope the new tool, currently under further research, will lead to more personalised care for those at risk of developing dementia.
“Ultimately, our goal is to give people more time,” Dr Petersen said, “time to plan, to act and to live well before memory problems take hold.”