A recent scientific study published in The Journal of Clinical Endocrinology & Metabolism looked at whether being overweight or obese (having a high body mass index, or BMI) can cause a higher risk of vascular-related dementia — a type of dementia linked to problems in blood vessels that supply the brain.
Dementia is a serious condition where people gradually lose memory and thinking skills. Previous publications on this journal show how good cardiovascular fitness may protect against dementia. According to scientific research, people who are obese tend to develop dementia more often than those with normal weight. However, scientists didn’t know whether excess weight actually caused the condition or was just related to it. This study used a special method called Mendelian randomization, which uses genetic information to help find out if one factor (like high BMI) actually leads to another (like dementia).
The research included large sets of data from population studies in Denmark, the United Kingdom and combined international groups. Researchers used genetic markers known to be linked with higher BMI. These genetic variants act like natural experiments — because genes are randomly passed down at birth, they are less likely to be influenced by lifestyle or social factors that can confuse traditional research.
The scientists analyzed this genetic data in several ways. They looked at how genetic risk for higher BMI was associated with the risk of vascular dementia, as well as other health problems that often occur with obesity, such as high blood pressure, high cholesterol, and high blood sugar.
Which are the key findings?
The study found that higher BMI does seem to play a causal role in raising the risk of vascular-related dementia. People with genetic profiles linked to higher BMI had a significantly higher chance of developing vascular dementia later in life. For each standard increase in BMI, the risk of vascular dementia rose noticeably. A part of this increased risk was explained by high blood pressure — suggesting that blood pressure plays a role in the link between obesity and dementia.
These results help scientists and doctors better understand how obesity affects brain health long term. Because high BMI causally contributes to vascular dementia, this means that maintaining a healthy weight and controlling blood pressure may reduce the chance of developing this serious brain condition.
The study highlights that obesity is not just associated with heart and metabolic diseases, but may also directly affect brain health. Future work can use this knowledge to help design better prevention strategies.
Editor of Daily 27.
Predoctoral researcher at the Department of Sociology in University of Barcelona.