Biomarkers in midlife adults without dementia may be linked to the earliest signs of waning cognition, researchers found.
Researchers have identified blood biomarkers for Alzheimer‘s disease that correlate with minor cognitive differences in midlife adults without dementia, according to a study led by University of California San Francisco (UCSF).
The study, published in The Lancet, found that biomarkers measuring tau and amyloid plaque were associated with a higher likelihood of cognitive decline in these participants. Among 1,350 participants aged 53 to 69, 6% exhibited high levels of these Alzheimer hallmarks in their blood.
“Alzheimer’s disease pathology begins years before symptoms emerge,” says Kristine Yaffe, MD, vice chair in the UCSF department of psychiatry and behavioral sciences, in a release. “Detecting the disease early means patients can target modifiable risk factors and maybe seek other care.”
Impact on Processing Speed and Executive Function
At the start of the study, participants with high biomarkers demonstrated lower processing speeds and lower executive function. These cognitive areas involve the ability to respond quickly to changing information and tasks such as planning, organizing, and staying on track.
Follow-up testing conducted five years later revealed that the high biomarker group faced two-and-a-half to four times the risk of rapid decline in verbal memory. Additionally, these participants had three to four times the risk of rapid decline in processing speed, indicating an increased likelihood of developing Alzheimer’s disease.
The study participants were long-term enrollees of the multisite CARDIA study. The cohort included 58% women, 45% Black participants, and 55% white participants.
Clinical Utility and Limitations
Blood tests for tau and amyloid are less expensive and noninvasive compared to traditional methods like brain scans or spinal fluid tests. While the Food and Drug Administration has approved these tests for patients already exhibiting symptoms, they could eventually be used for asymptomatic individuals, according to the study.
However, Yaffe notes that these blood tests should be used with caution due to the possibility of false positives. Additionally, the tests only detect Alzheimer’s disease and not other forms of dementia, which account for 60% to 70% of all 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,” says Yaffe, vice chair in the UCSF department of psychiatry and behavioral sciences, in a release.
The research was primarily funded by the National Institutes of Health.
