Another Reason to Lose Weight: "Obese Individuals Are More Prone to Dementia"

Increased BMI Raises Risk of Vascular Dementia
Causal Link Confirmed Between Obesity, Hypertension, and Cerebrovascular Damage

A large-scale study has found that obesity is a direct risk factor for vascular dementia. In particular, increases in body mass index (BMI) were shown to significantly raise the risk of vascular dementia, with high blood pressure identified as a major mediating factor.

On January 22 (local time), The Washington Post reported these findings, citing research by Professor Ruth Frikke-Schmidt's team at the University of Copenhagen, Denmark, published in the international journal The Journal of Clinical Endocrinology & Metabolism.

The researchers analyzed data from more than 500,000 people, including 126,655 participants from the Copenhagen City Heart Study (CCHS) and 377,755 participants from the UK Biobank. To move beyond a simple correlation between increased body mass and the onset of dementia, the team employed the Mendelian Randomization (MR) method. This approach uses genetic variations to create conditions similar to clinical trials, and is considered highly reliable for studying causal relationships between obesity and dementia.

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The analysis showed that for every one standard deviation (SD) increase in BMI, the risk of developing vascular dementia rose by an average of 1.63 times. Even when using different analytical models, the risk ranged from a minimum of 1.54 times to a maximum of 1.98 times higher. Across all analyses, the trend was consistent: higher BMI led to an increased risk of dementia. In contrast, no significant correlation was found between BMI and Alzheimer's disease.

The research team stated, "About 18% of the effect of increased BMI can be explained by systolic blood pressure, and 25% by diastolic blood pressure." High blood pressure causes damage to cerebral blood vessels and repeatedly induces microinfarctions, which ultimately lead to vascular dementia. Professor Frikke-Schmidt said, "This study demonstrates that high BMI and high blood pressure are direct causes of dementia," adding, "Weight management and blood pressure control can be key strategies for dementia prevention."

Experts also point out that vascular dementia presents differently from Alzheimer's disease. In vascular dementia, impairments in executive function, judgment, and planning appear before memory decline. Another characteristic is that after a relatively stable period, there is a sudden stepwise deterioration in function.

Recent findings have also shown that weight loss medications have not demonstrated clear benefits in halting cognitive decline in early-stage Alzheimer's patients. The researchers interpreted this to mean that managing weight and blood pressure is much more important before cognitive decline begins, rather than after it has already started.