Scientists from the University of Bristol have found that a lifelong genetic predisposition to excess body weight may increase the risk of vascular dementia later in life. The study results were published in The Journal of Clinical Endocrinology & Metabolism (JCEM).

The researchers analyzed large population datasets and used Mendelian randomization — a genetic method that allows scientists to assess how inherited factors influence disease risk. This approach helps avoid bias related to weight loss that may occur after a disease has already begun.

The analysis showed that a genetic tendency toward a higher body mass index (BMI — the ratio of body weight to height) is associated with an increased likelihood of developing dementia caused by damage to the brain’s blood vessels. An increase in BMI of about four to five points — from borderline to clearly elevated levels — was linked to roughly a 60% higher risk of vascular dementia.

Arterial blood pressure appeared to be the key factor underlying this relationship. Excess adipose tissue contributes to higher blood pressure, while chronic hypertension gradually damages arterial walls, including the small vessels of the brain. Over time, this leads to impaired blood supply, reduced oxygen delivery, and progressive cognitive decline.

The strongest association was observed specifically for dementia forms related to vascular disorders. The effect remained significant even after accounting for cholesterol and blood glucose levels.

The authors note that most participants were of European ancestry, meaning additional studies in other populations are needed to confirm the findings. Nevertheless, the researchers emphasize that maintaining a healthy body weight and controlling blood pressure may help reduce not only the risk of stroke and cardiovascular disease, but also the likelihood of future cognitive impairment.