Early-life Obesity Impacts Children's Learning and Memory
California: A new study by Brown University epidemiologists found that children on the threshold of obesity or overweight in the first two years of life had lower perceptual reasoning and working memory scores than lean children when tested at ages five and eight. The study also indicated that IQ scores may be lower for higher-weight children.
"The first few years of life are critical for cognition development, and we investigated whether early-life adiposity has an impact on cognitive abilities later in life," said Nan Li, lead author and a postdoctoral research associate in Brown's Department of Epidemiology, who worked with faculty member Joseph Braun on the study.
For the study, featured in the June issue of Obesity, Li, Braun and their coauthors focused on a group of children whose weight, relative to their height or length, was known at age one and/or age two, and who later underwent a series of cognitive tests.
The children in the study took a series of tests that assessed their general cognitive abilities, memory, attention and impulsivity, according to the study.
One set of tests measured children's overall intellectual abilities, including verbal abilities and organization skills. A set of computerized tasks assessed children's attention, impulsivity and executive control, and a maze game tested the children's visual-spatial memory. A sequencing test assessed working memory, and another set of tests assessed perceptual reasoning.
The researchers found that weight status did not appear to affect performance on some of the tests, but had three significant impacts.
"Excess early-life adiposity was associated with lower IQ, perceptual reasoning and working memory scores at school-age," Li said.
IQ refers to overall cognitive abilities, while working memory falls under the domain of executive function, which the authors described in the paper as the set of self-regulatory cognitive processes that aid in managing thoughts, emotions and goal-directed behaviors.
"Executive function is associated with academic success in children and is critical for physical health and success throughout life," the authors wrote.
Perceptual reasoning tests, according to Li, "assess children's ability to examine a problem, draw upon visual-motor and visual-spatial skills, organize their thoughts, create solutions and then test those solutions."
The authors pointed out that the sample size of their study was limited and that further studies should be conducted to confirm their findings. Future work could also investigate the impact of early-life weight status on school performance, attention-deficit/hyperactivity disorder diagnoses and special education use.