A study of over 2300 healthy French men and women finds that a high body mass index is associated with lower scores on cognitive tests. The participants, who were between the ages of 32 and 62, were initially tested in 1996 and again five years later.
In the study, to be published in the October 10, 2006 issue of Neurology, researchers assessed cognitive function through the use of four cognitive tests. They discovered word memory recall was affected as people with a BMI of 20 remembered an average of nine out of 16 words, while people with a BMI of 30 remembered an average of seven out of 16 words.
“A higher BMI in 1996 was also associated with a higher cognitive decline at follow-up in 2001,” said study author Maxime Cournot, MD, with Toulouse University Hospital and the National Institute of Health and Medical Research in Toulouse, France. “The study’s findings may be due to a host of factors including the thickening and hardening of cerebral vessels because of obesity or possibly the development of insulin resistance.”
While the study found no association between changes in BMI between 1996 and 2001 and cognitive performance, the study did find a slight improvement in cognitive test scores during the five-year time frame.
“This slight improvement may be due to the relatively young age of the participants, who likely had a low incidence of cognitive decline over five years,” said Cournot. “The improvement could also be due to an increased familiarization with the tests at follow-up.”
Cournot says the prevalence of both dementia and obesity is increasing in epidemic proportions, and the link between BMI and cognitive function could serve as a tool in dementia prevention by managing obesity in middle-age adults.