Early Alzheimer’s clues found in blood: Researchers link tau and amyloid markers to midlife cognitive changes
Scientists at UC San Francisco discovered blood biomarkers linked to tau and amyloid changes may signal early cognitive decline in midlife adults before Alzheimer's symptoms appear.
A groundbreaking study has discovered that some blood markers associated with Alzheimer's disease could already be impacting brain function before dementia symptoms ever set in potentially during middle age. According to the researchers from the University of California San Francisco (UCSF) this findings could lead to the ability to detect people who are at greater risk for the onset of Alzheimer's years before it occurs.
The study which was published on 28 May in The Lancetlooked at blood markers linked with the two key Alzheimer's disease markers which are amyloid plaques and tau proteins. They discovered that approximately 6 per cent of the 1,350 participants between the ages of 53 and 69 were found to have high levels of both amyloid and tau in their blood.
Changes in brain function that occur at an early stage
According to the study people with higher levels of biomarkers had poorer functioning in the areas of processing speed and executive functioning.
Processing speed is the brain's ability to respond quickly and efficiently to information such as during a conversation or driving. Executive function is a group of mental processes that allows us to plan, organize, multi-task and make decisions in daily life.
Problems with these functions could be among the first measurable changes that happen in the brain and may be an indicator of Alzheimer's disease.
Those who had higher biomarkers also had significantly higher risk of fast cognitive decline over the next five years. The study results showed they were at almost 2.5 to 4 times greater risk of verbal memory decline and about 3 to 4 times greater risk of the worsening of processing speed.
The subjects were from the long-term CARDIA study at several study centres in the United States. The percentage of female participants was 58 per cent and 45 per cent of the total were Black participants.
Importance of early detection
Senior author Kristine Yaffe, vice chair of the UCSF Department of Psychiatry and Behavioral Sciences emphasized that Alzheimer's disease is a neurological disorder that can start many years before it is apparent. He said, "Alzheimer's disease pathology begins years before symptoms emerge. Detecting the disease early means patients can target modifiable risk factors and maybe seek other care."
Dr. Yaffe has previously studied extensively how lifestyle and health factors influence risk of dementia. Factors such as smoking, depression, inactivity, heart disease and low levels of cognitive stimulation are important modifiable risk factors. Researchers say that changes to these risk factors could prevent or postpone up to 40 per cent of dementia cases.
Easier screening options
Today, Alzheimer's disease is diagnosed primarily by costly brain imaging or by drawing spinal fluid from the body and testing it. Although blood biomarker testing is approved for individuals with symptoms, researchers hope that it will be useful to identify at-risk individuals early in life in the future.
Experts caution that tests are not flawless. Yaffe stated, "There's a possibility of false positives and they can only be used for Alzheimer's, not other dementias, meaning about 60 per cent to 70 per cent of all dementia cases. But for some people who discover they have the biomarkers, testing could open a window to embark on interventions that may postpone Alzheimer's onset."
Disclaimer: This article is for informational purposes only and is not a medical advice. Always consult a qualified healthcare professional for diagnosis, screening or treatment related to Alzheimer's disease.
