THURSDAY, Jan. 22, 2026 (HealthDay News) -- High body mass index (BMI) is associated with a higher risk for vascular-related dementia, with the association partially mediated by high blood pressure, according to a study published online Jan. 22 in the Journal of Clinical Endocrinology & Metabolism.Liv Tybjærg Nordestgaard, M.D., Ph.D., from Copenhagen University Hospital-Rigshospitalet in Denmark, and colleagues examined whether high BMI is a causal risk factor for vascular-related dementia in prospective cohort studies of the general populations from the Copenhagen area and from across the United Kingdom and using consortia data. One-sample Mendelian randomization (MR), two-sample MR, and MR in mediation analyses were included as interventions.The researchers found that the odds ratio for one-standard deviation higher BMI in predicting vascular-related dementia was 1.63 in a meta-analysis of two one-sample MR studies. Per one-standard deviation higher BMI, the odds ratio for vascular-related dementia was 1.54, 1.87, and 1.98 using the inverse variance weighted, weighted median, and weighted mode methods, respectively, in a two-sample MR study. Directionally consistent results were seen for MR analyses, including extended numbers of genetic variants. Systolic and diastolic blood pressure mediated 18 and 25 percent, respectively, of the genetic effect of BMI on vascular-related dementia."This study shows that high body weight and high blood pressure are not just warning signs, but direct causes of dementia," coauthor Ruth Frikke-Schmidt, M.D., also from Copenhagen University Hospital-Rigshospitalet, said in a statement. "That makes them highly actionable targets for prevention."Abstract/Full Text.Sign up for our weekly HealthDay newsletter