# Is Obesity Tied to Dementia Onset?
Recent research has uncovered a significant connection between obesity and the development of Alzheimer’s disease, one of the most common forms of dementia. A groundbreaking study from Washington University School of Medicine in St. Louis examined how body weight influences the biological markers associated with Alzheimer’s disease in the brain.
The study tracked 407 participants over five years, measuring blood biomarkers related to Alzheimer’s disease and using brain imaging scans called amyloid PET scans. Researchers discovered that people with obesity showed a dramatically faster increase in Alzheimer’s disease blood biomarkers compared to people of healthy weight. Specifically, blood biomarker values rose up to 95 percent faster in obese individuals. Additionally, people with obesity experienced a 29 to 95 percent faster increase in certain plasma protein levels and a 24 percent faster rise in another key brain protein marker.
The research also found that obesity was associated with a 3.7 percent faster increase in amyloid accumulation in the brain. Amyloid is a protein that builds up in the brains of people with Alzheimer’s disease and is linked to cognitive decline and memory problems.
One interesting finding emerged when researchers looked at the beginning of the study. At baseline, people with obesity actually had lower blood biomarker levels and less overall amyloid burden in their brains compared to people without obesity. However, this pattern reversed over time. The researchers believe this initial difference occurred because people with obesity have larger blood volumes, which dilutes the concentration of biomarkers in their blood. As time went on, the biomarkers in obese individuals increased much more rapidly than in those without obesity.
The blood tests used in this research proved to be more sensitive than the brain imaging scans at detecting how obesity influences Alzheimer’s disease development. This means blood tests may be particularly useful for tracking how obesity affects the disease over time.
The implications of this research are significant for clinical practice. One expert noted that while obesity is linked to a faster rate of increase in Alzheimer’s disease blood biomarkers and amyloid buildup over time, this effect is not immediately visible at the start. This suggests that weight management could potentially be used as a therapeutic strategy to slow disease progression. People with obesity might benefit from earlier screening for Alzheimer’s disease, more frequent monitoring, or more aggressive interventions to reduce their risk.
It is worth noting that some older research has suggested an “obesity paradox” in dementia, where certain studies reported inverse associations between obesity and dementia risk. However, the recent longitudinal evidence from the Washington University study provides compelling new data showing that obesity accelerates the biological changes associated with Alzheimer’s disease.
The connection between obesity and Alzheimer’s disease appears to be rooted in how excess weight affects the accumulation of harmful proteins in the brain. This research opens new possibilities for using weight management as a way to potentially slow or prevent the development of dementia in people with obesity.
Sources
https://www.medicalnewstoday.com/articles/obesity-may-hasten-alzheimers-disease-development
https://www.nutritioninsight.com/news/obesity-alzheimers-disease-brain-health-weight.html
https://www.sciencedaily.com/releases/2025/12/251210092019.htm
