Researchers describe how fat raises risk of dementia

Dementia is a major global public health hazard that currently affects 50 million people and is expected to impact more than 150 million people by 2050. Obesity, as measured by the body mass index, is a persistent global issue (BMI). Obesity in middle age has been linked to an increased risk of dementia in previous studies. However, it is yet uncertain if BMI and dementia risk are linked.

Researchers from Boston University Chobanian & Avedisian School of Medicine and the Chinese Academy of Medical Sciences & Peking Union Medical College have shown that various patterns of BMI changes during a person’s life cycle may be a predictor of dementia risk.

“These findings are important because previous studies that looked at weight trajectories didn’t consider how patterns of weight gain/stability/loss might help signal that dementia is potentially imminent,” explained corresponding author Rhoda Au, PhD, professor of anatomy and neurobiology.

“These findings are important because previous studies that looked at weight trajectories didn’t consider how patterns of weight gain/stability/loss might help signal that dementia is potentially imminent,” explained corresponding author Rhoda Au, PhD, professor of anatomy and neurobiology.

A set of individuals in the Framingham Heart Study were tracked for 39 years and their weight was assessed every 2-4 years. The researchers studied distinct weight trends (stable, growth, loss) between people who became demented and those who did not. They discovered that the general trend of decreased BMI was linked to an increased chance of getting dementia.

Further investigation revealed a subgroup with a trend of first increasing BMI followed by dropping BMI, both happening within midlife, which looked to be key to the declining BMI-dementia connection.
Weight monitoring is generally simple for people, family members, and primary care providers, according to Au.

“If after a steady increase in weight that is common as one gets older, there is an unexpected shift to losing weight post midlife, it might be good to consult with one’s healthcare provider and pinpoint why. There are some potential treatments emerging where early detection might be critical in the effectiveness of any of these treatments as they are approved and become available,” she added.

The researchers hope this study will illustrate that the seeds for dementia risk are being sowed across many years, likely even across the entire lifespan. “Dementia is not necessarily inevitable and monitoring risk indicators such as something as easy to notice as weight patterns, might offer opportunities for early intervention that can change the trajectory of disease onset and progression.”