A small study indicates regular blood tests could be a useful addition to brain scans that track the progression of Alzheimer’s disease.
Obesity may speed up the development of Alzheimer’s disease, a new analysis shows.
The findings indicate blood tests may be more sensitive than brain scans alone in identifying how obesity affects the early stages of dementia, the researchers said.
“This is the first time we’ve shown the relationship between obesity and Alzheimer’s as measured by blood biomarker tests,” said Dr Cyrus Raji, one of the study’s authors and an associate professor of radiology and neurology at the US-based Washington University School of Medicine in St. Louis.
“The fact that we can track the predictive influence of obesity on rising blood biomarkers more sensitively than PET [positron emission tomography] is what astonished me in this study,” Raji added in a statement.
The findings, which have not yet been published in a peer-reviewed journal, will be presented on Tuesday at the annual meeting of the Radiological Society of North America.
Raji’s team tracked 407 people over five years, using blood samples and PET scans to identify signs of Alzheimer’s. PET scans measure amyloid plaque buildup in the brain, which is a key sign of Alzheimer’s, while blood tests show the level of proteins and other biomarkers linked to cognitive decline.
Over time, Alzheimer’s pathology progressed more quickly in people with obesity than in those without the condition, the analysis found.
Obesity was linked to a 24 per cent faster increase in the protein plasma NfL, a 29 per cent to 95 per cent faster increase in the blood biomarker plasma pTau217, and a 3.7 per cent faster accumulation of amyloid plaques.
Raji said the findings could help doctors track Alzheimer’s progression over time. For example, blood biomarkers and brain scans could help them understand the effectiveness of drugs designed to combat amyloid buildup, he said.
“It’s marvellous that we have these blood biomarkers to track the molecular pathology of Alzheimer’s disease, and MRI scans to track additional evidence of brain degeneration and response to various treatments,” Raji said.
Obesity is a known risk factor for Alzheimer’s. People with obesity are also more likely to have high blood pressure, type 2 diabetes, and less physical activity – all of which contribute to dementia risk.
An estimated 57 million people worldwide have dementia. Alzheimer’s is the most common form, causing 60 per cent to 70 per cent of cases, according to the World Health Organization (WHO).
