A new study has revealed that obesity can significantly speed up the development of Alzheimer's disease, with blood biomarkers increasing up to 95% faster in obese individuals compared to those of a healthy weight. The research, set to be presented at the annual meeting of the Radiological Society of North America (RSNA), analyzed five years of data from 407 participants, including brain scans and blood samples.
The study focused on a blood test measuring p-tau217, a protein that indicates the presence of amyloid plaques—sticky protein clumps characteristic of Alzheimer's. Initially, researchers observed that higher BMI was associated with lower levels of these biomarkers and fewer plaques, but this was attributed to dilution from increased blood volume in obese individuals. Lead author Soheil Mohammadi warned that this could be misleading, suggesting a lower risk of Alzheimer's in obese people.
However, long-term analysis revealed that obese participants experienced a 29% to 95% faster rate of increase in p-tau217 ratio levels, indicating accelerated Alzheimer's pathology. Senior author Dr. Cyrus Raji noted that blood tests proved more sensitive than brain scans in capturing obesity's impact on Alzheimer's development. He added that this work is foundational for future studies, particularly in monitoring the effects of weight loss drugs on Alzheimer's biomarkers.
In the UK, there are approximately 982,000 people with dementia, and obesity is a known risk factor. The Alzheimer's Society reports that obesity between ages 35 and 65 can increase dementia risk by about a third, partly due to links with high blood pressure and type 2 diabetes. This study provides the first direct evidence of a link between obesity and Alzheimer's using blood tests.
