Cognitive decline is a normal part of ageing, but it may hit overweight people harder, according to groundbreaking research.
American researchers have discovered that people with a higher BMI tend to have more inflammation in the body, which in turn may impair cognition.
Previous studies established a link between BMI and cognitive decline, and inflammation and cognitive decline, but this is the first study to link all three.
University of Arizona Phd student and lead author Kyle Bourassa said establishing which mechanisms might be at play “is important to be able to intervene” to reverse the process.
In two samples of thousands of English people age 50 and over, Bourassa and co-author professor David Sbarra discovered a link between BMI, CRP – a protein in the blood linked to systemic inflammation – and cognition.
“The higher participants’ body mass at the first time point in the study,” Bourassa said, “the greater the change in their CRP levels over the next four years.
“Change in CRP over four years then predicted change in cognition six years after the start of the study. The body mass of these people predicted their cognitive decline through their levels of systemic inflammation.”
But the scientists added that the study hadn’t proved a causal link between BMI, inflammation and brain power.
“We cannot confirm causality until we reduce body mass experimentally, then examine the downstream effects on inflammation and cognition,” Sbarra said.
The scientists hope the results will shed light on possible interventions, including exercise and anti-inflammatory drugs.
The study was published in the journal Brain, Behaviour, and Imunnity.