Hoher Body-Mass-Index als direkte Ursache für vaskuläre Demenz identifiziert. Eine neue genetische Analyse zeigt, dass die Aufrechterhaltung eines gesunden Gewichts und die Kontrolle des Bluthochdrucks eine erhebliche Anzahl von Demenzfällen verhindern könnten.

>Excess body weight appears to be a direct cause of vascular dementia, with the damage largely driven by high blood pressure. A new genetic analysis indicates that maintaining a healthy weight and managing hypertension could prevent a substantial number of dementia cases. These findings were detailed in a [study](https://doi.org/10.1210/clinem/dgaf662) published recently in The Journal of Clinical Endocrinology & Metabolism.

>The relationship between obesity and cognitive decline has challenged researchers for decades. Previous observational studies frequently produced contradictory results regarding how body weight influences brain health. Some research indicated that obesity in midlife increased dementia risk. Other studies suggested that high body weight in late life might actually protect against the disease. This paradox often stems from the limitations of traditional observational research.

>In the early stages of dementia, patients frequently lose weight due to a loss of appetite or metabolic changes. This weight loss can make it appear as though being thin carries a higher risk, when in reality the disease caused the weight loss.

>To resolve these conflicting signals, a research team led by Liv Tybjærg Nordestgaard and senior author Ruth Frikke-Schmidt sought to determine if high body mass index (BMI) causes vascular dementia. Frikke-Schmidt is a professor and chief physician at Copenhagen University Hospital and the University of Copenhagen. The team aimed to move beyond simple associations to establish a cause-and-effect relationship. They also sought to identify the biological mechanisms that connect excess weight to brain damage.

>The researchers utilized a sophisticated analytical method known as Mendelian randomization. This technique acts as a natural simulation of a randomized controlled trial. It relies on the random assortment of genetic variants that occurs during conception. Humans inherit genetic markers that predispose them to a slightly higher or lower BMI. These markers are fixed at birth and are generally unaffected by lifestyle choices, socioeconomic status, or environmental factors. Because these genetic variants are randomly assigned, they separate the biological effects of body mass from confounding variables like diet or exercise.