A longitudinal study finds blood-based biomarkers more sensitive than PET scans in detecting obesity’s impact on Alzheimer’s pathology.
Blood-based biomarker values increased up to 95% faster in individuals with obesity compared to non-obese individuals, according to a study presented at the annual meeting of the Radiological Society of North America.
The research represents the initial evaluation of obesity’s impact on Alzheimer’s disease blood biomarkers, analyzing five-year data from 407 participants in the Alzheimer’s Disease Neuroimaging Initiative.
“This is the first time we’ve shown the relationship between obesity and Alzheimer’s disease as measured by blood biomarker tests,” says Cyrus Raji, MD, PhD, senior author of the study and a principal investigator in the Neuroimaging Labs Research Center at Mallinckrodt Institute of Radiology at Washington University School of Medicine in St Louis, in a release.
Blood Tests Outperform PET Imaging
Researchers tested plasma samples for blood-based biomarkers associated with Alzheimer’s disease, including pTau217 levels, neurofilament light chain (NfL), and plasma GFAP using six leading commercial tests. The team also conducted amyloid positron emission tomography (PET) scans to measure brain amyloid burden.
The analysis revealed that blood tests demonstrated greater sensitivity than PET scans in capturing obesity’s impact on Alzheimer’s pathology. Participants with obesity showed a 29% to 95% faster rate of increase in plasma pTau217 ratio levels, while baseline obesity led to a 24% faster rate of increase in plasma NfL and a 3.7% faster rate of increase in amyloid accumulation.
“The fact that we can track the predictive influence of obesity on rising blood biomarkers more sensitively than PET is what astonished me in this study,” says Raji in a release.
Longitudinal Data Reveals Hidden Risk
Initial baseline measurements showed lower blood-based biomarkers in obese individuals, potentially masking the true disease progression risk. Researchers attributed this finding to dilution from higher blood volume in obese patients.
“In fact, by relying on the baseline measurements, you could be fooled into thinking that the people with obesity had a lower pathology of Alzheimer’s disease,” says study lead author Soheil Mohammadi, MD, MPH, postdoctoral research associate at Mallinckrodt Institute of Radiology, in a release. “We need the longitudinal data to fully understand how obesity impacts the development of Alzheimer’s pathology.”
The longitudinal approach proved essential for detecting the accelerated disease progression over time in obese participants.
Clinical Practice Implications
The research suggests that obesity status should be considered when interpreting blood biomarker results and tracking disease progression.
“According to the 2024 report of the Lancet Commission, 14 modifiable risk factors total approximately 45%, or close to half, of the risk for Alzheimer’s disease,” says Mohammadi in a release. “If we can reduce any of those risk factors, we can significantly reduce Alzheimer’s cases or lengthen the amount of time until the onset of the disease.”
Raji anticipates that longitudinal assessments with blood biomarkers combined with brain health imaging will become standard practice for monitoring treatment with anti-amyloid drugs.
“This is such profound science to follow right now because we have drugs that can treat obesity quite powerfully, which means we could track the effect of weight loss drugs on Alzheimer’s biomarkers in future studies,” says Raji in a release.
The research team included co-authors Farzaneh Rahmani, MD, MPH, Mahsa Dolatshahi, MD, MPH, and Suzanne E Schindler, MD, PhD.
ID 168703200 | Alzheimer © Designer491 | Dreamstime.com
