Being overweight may lead to accelerated cognitive decline, according to new research.
Cognitive decline is a normal process. As people age, it often becomes harder to remember things and think as clearly as when they were younger. In otherwise healthy adults, these changes are gradual and subtle.
The new study found higher body mass index over time led to more rapid declines in cognitive functions, memory, and executive functioning than what is typically seen in aging adults. That includes things such as managing emotions, organizing and planning tasks, concentrating, and more.
The researchers relied on data from a nationally representative study that followed more than 8,200 people over the age of 50 for 24 years.
The present study found that every unit increase in BMI led to a more rapid decline in brain health.
But it’s not all bad news.
“We found that if people managed their weight, they could significantly lower their rate of cognitive decline in just two years,” says Suhang Song, lead author of the study and an assistant professor in University of Georgia’s College of Public Health.
“That makes BMI one of the most easily modifiable risk factors when it comes to aging well.”
The researchers found the strongest correlation between BMI and cognitive decline at year eight of the study. The effect was most pronounced in adults over 65.
Defined as having a BMI of 30 or higher, obesity negatively affects brain health. But it’s not clear exactly how, according to the researchers.
It’s likely that extra weight results in inflammation, reduced blood flow and insulin resistance. That may lead to cognitive impairment, Alzheimer’s disease, and related dementias.
Two out of every five Americans are considered obese based on their BMI alone, according to the Centers for Disease Control and Prevention.
Some researchers are pushing for an expanded definition of obesity that also accounts for additional factors including waist size and weight-related health conditions. Under that definition, the percentage of Americans with obesity jumps to 75%.
Meanwhile, more than 7 million people are living with dementia in the US. And that number is predicted to double by 2050, the researchers say.
“There are no cures for dementia,” Song says, “which is why it is critical to identify and address any modifiable risk factors we can find to prevent it.”
The study appears in the Journal of Neurology.
Source: University of Georgia
