Study finds link between BMI and dementia risk

From the 50 million cases that exist today, it is predicted that there will be more than 150 million dementia cases globally by 2050. Body mass index (BMI) is a common way to evaluate obesity, and it’s still a problem throughout the world. Previous studies have shown that obesity in middle life may increase the risk of dementia. However, it is still unclear how BMI and the risk of dementia are related.

The Alzheimer’s Association’s journal, Alzheimer’s & Dementia: The Journal, published these findings online. Researchers from the Chobanian & Avedisian School of Medicine at Boston University, the Chinese Academy of Medical Sciences, and Peking Union Medical College have shown that various patterns of BMI changes throughout the course of a person’s life may be a sign 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.

A set of individuals in the Framingham Heart Study were tracked for 39 years while having their weight checked around every 2-4 years. The researchers investigated various weight trends (stable, growth, loss) between those who developed schizophrenia and others who did not.

They discovered a greater risk of dementia development was linked to the general trend of decreased BMI. Further investigation revealed a subgroup, though, that looked to be the key to the falling BMI-dementia relationship, with a pattern of initial growing BMI followed by dropping BMI, both happening in midlife.

Au emphasises how simple it is for patients, family members, and primary care providers to keep track of their weight.

“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.