High BMI linked to vascular dementia risk

High body mass index (BMI) could cause a higher risk of vascular-related dementia (a combination of vascular + unspecified dementia), according to new research from the University of Bristol and University Hospital of Copenhagen (Rigshospitalet and Herlev-Gentofte hospital). The researchers found that the effect of high BMI on dementia mainly works through high blood pressure.

The study published in The Journal of Clinical Endocrinology & Metabolism today [22 January] has shown that many dementia cases could be prevented if high BMI and high blood pressure is treated or prevented.

Previous observational studies have already found a link between midlife obesity and high risk of dementia, including vascular dementia. However, those studies did not uncover whether the obesity causes an increase in dementia risk or whether there is some other factor involved affecting both obesity and dementia risk.

The new study analysed population health data from Denmark, the UK and around the world using a powerful approach called Mendelian Randomisation. This statistical, computational technique looks at genetics and health data to see health patterns across large populations.

The researchers found that high BMI does increase the risk of vascular-related dementia. They also found that high blood pressure is the main factor in this association, pointing to the potential of treating high blood pressure to reduce dementia risk.

First author Dr. Liv Tybjærg Nordestgaard, who initiated the project in Copenhagen and extended the work while at the University of Bristol, and who is now at the Department of Clinical Biochemistry at Copenhagen University Hospital -Bispebjerg and Frederiksberg, said: "Dementia is a devastating disease that currently affects 50 million individuals worldwide. Unfortunately, treatment and prevention options are scarce. Our study highlights the potential for reducing vascular-related dementia risk by addressing high BMI and/or high blood pressure in the population."

Weight-loss medication has recently been tested for halting cognitive decline in early phases of Alzheimer's disease, but with no beneficial effect. It remains, however, to be tested whether weight-loss medication initiated before the appearance of cognitive symptoms may be protective against dementia. Our study supports that early weight-loss interventions could prevent dementia, and especially vascular-related dementia."

Professor Ruth Frikke-Schmidt, Department of Clinical Biochemistry, Copenhagen University Hospital - Rigshospitalet, and senior author

This research was funded by The Research Council at the Capital Region of Denmark; Independent Research Fund Denmark (grant ID: 10.46540/3100-00007B); the Lundbeck Foundation; the Danish Heart Foundation; the Research Fund at Sygeforsikringen Danmark; and the Medical Research Council.