• Posted December 2, 2025

Obesity Could Speed Alzheimer's Progression, Study Suggests

Obesity might contribute to faster progression of Alzheimer’s disease, a new study says.

Some blood markers associated with Alzheimer’s increased nearly twice as fast among people with obesity compared to people who didn't have obesity, according to results presented today at the Radiological Society of North America’s annual meeting in Chicago.

“This is the first time we’ve shown the relationship between obesity and Alzheimer’s disease as measured by blood biomarker tests,” senior researcher Dr. Cyrus Raji, a principal investigator in the Neuroimaging Labs Research Center of the Mallinckrodt Institute of Radiology (MIR) at Washington University School of Medicine in St. Louis.

For the study, researchers tracked five-year data on more than 400 participants in an ongoing brain imaging study of Alzheimer’s patients.

Results showed that people with obesity had blood biomarkers for Alzheimer’s that rose more rapidly, including:

• Tau proteins, which form toxic clumps in the brains of Alzheimer’s patients.

• Protein fragments of neurofilament light chain (NfL), which are released from damaged or dying brain cells.

• Glial fibrillary acidic protein, a protein produced by cells that heal and protect neurons in the brain and spinal cord.

Overall, tau levels increased up to 95% faster in people with obesity, results show. There also was a 24% faster rate of increase in NfL levels in participants with obesity versus those with Alzheimer's without obesity.

Overall, blood tests proved better than PET medical imaging scans in capturing the impact of obesity on Alzheimer’s, researchers concluded.

“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,” Raji said.

These results imply that obesity might be a risk factor for Alzheimer’s, said lead researcher Dr. Soheil Mohammadi, a postdoctoral research associate at MIR.

“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,” Mohammadi said in a news 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 believes that in the future doctors will use both blood tests and brain imaging scans to track Alzheimer’s patients, particularly those being treated with newly approved drugs meant to slow the disease’s progression.

“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,” Raji said.

“It’s marvelous 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 continued. “This work is foundational for future studies and treatment trials.”

Results presented at medical meetings should be considered preliminary until they're published in a peer-reviewed journal.

More information

The Alzheimer’s Association has more about the biomarkers of Alzheimer’s.

SOURCE: Radiological Society of North America, news release, Dec. 2, 2025