Higher BMI increases vascular dementia risk by harming brain blood vessels, study finds.

A new study published on January 22, 2026, provides strong evidence that higher body mass index (BMI) directly increases the risk of vascular dementia, the second most common form of dementia, by damaging brain blood vessels. Using genetic data and advanced statistical methods, researchers analyzed over 500,000 individuals from Denmark and the UK and found that each 4.5-point rise in BMI correlated with a significantly higher risk of vascular dementia, with high blood pressure explaining a major portion of this link. Experts say maintaining a healthy weight and managing blood pressure through diet, exercise, and regular monitoring—ideally below 120/80 mm Hg—can help prevent dementia, as there is currently no cure. The findings support the idea that heart-healthy habits protect brain health and highlight the importance of early intervention, though the study’s results may not fully apply to non-White populations due to limited diversity in the sample.