Midlife blood test could predict cognitive decline

Medical Laboratory Scientist at bench with micropipettes. —
Courtesy U.S. National Institutes of Health (Public Domain)

Scientists based at the University of Michigan have connected two blood biomarkers to changes in cognitive function in women in midlife. The significance is that this opens up a potentially useful path towards developing a non-invasive, earlier detection and intervention process for Alzheimer’s disease and other dementias.

The study analysed two blood-based serum biomarkers, amyloid β (Aβ)42, Aβ42/40 ratio and phosphorylated tau181 (p-tau181), and tracked their levels in middle-aged women. The researchers compared results of a series of neurological function tests.

The analysis discovered that higher levels of p-tau 181 were linked to accelerated cognitive decline. In addition, lower AB 42/40 levels were associated with faster cognitive decline. The data came from 192 middle-aged women who were followed for 14 years through the Study on Women’s Health Across the Nation, Michigan Cohort.

The findings suggest that midlife blood AD biomarker assessments may serve as early predictors of cognitive decline, offering an opportunity for early detection and prevention before development of irreversible dementia.

In addition to the possibility of earlier intervention for Alzheimer’s disease and other forms of dementia, the blood biomarker tests such as those studied by the researchers could also lead to less invasive, possibly more affordable methods of neurological testing. Such investigations currently require lumbar punctures for cerebral fluid and expensive PET scans for imaging.

The presence of the biomarkers does not mean there is a case of Alzheimer’s Disease. However, these markers are a central part of neuropathological changes. As such, these pathological changes are important to know of earlier than later.

The researchers chose midlife as a “pivotal period” to test for and identify cognitive decline due to two major changes in women: menopausal transition and higher prevalence of cardiometabolic risk factors such as hypertension and diabetes, which are also associated with elevated risk of cognitive decline and dementia in older age.

The findings have been published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. The research paper is titled “Blood-based biomarkers for Alzheimer’s disease and cognitive function from mid- to late life.”

While the results are promising, there is a need for a larger and more diverse sample. The researchers plan to carry out further examinations.