Obese children have different brain structures, University of Cambridge researchers find
Children who are obese have different brain structures to those who are of ‘normal’ weights, University of Cambridge researchers have found.
Working with Yale University, they analysed data from 2,700 children between the ages of 9-11 years.
Those who were obese had significantly thinner cortex - the outer layer of the brain often called the ‘grey matter’.
The researchers also found thinning in the pre-frontal region of the cortex, an area associated with cognitive control.
And they confirmed that an increased BMI, or body mass index, was associated with poorer performance in tests measuring executive function.
Dr Lisa Ronan, the study’s first author from the Department of Psychiatry at the University of Cambridge, said: “We saw very clear differences in brain structure between children who were obese and children who were a healthy weight.
“It’s important to stress that the data does not show changes over time, so we cannot say whether being obese has changed the structure of these children’s brain or whether innate differences in their brains lead them to become obese.”
Worldwide, it is thought about 124 million children are obese. Almost one in five children starting primary school in the UK are overweight or obese - and the proportion rises to one in three by the time they begin secondary school.
It is known that children who are overweight or obese are more likely to become obese adults, leaving them at risk of poorer health in later life, including diabetes, heart disease and cancer.
Earlier studies have shown that those who are overweight typically score lower on measures of executive function, which covers areas such as self-control, decision making, working memory and response to rewards.
The executive set of processes enable planning, problem solving, flexible reasoning and regulation of behaviours and emotions.
The researchers sought to explore if the link existed in children. They studied data from youngsters recruited as part of the National Institutes of Health Adolescent Brain Cognitive Development (NIH ABCD) Study.
Comparing the average thickness of the cortex to each child’s body mass index, they found a significant reduction in those who were overweight, even when factors including age, sex, race, parental education, household income and birth-weight were taken into account.
As the NIH ABCD Study will follow the children as they grow older, Dr Ronan hopes they will be able to learn if the structural differences found in the brain change over time and exactly how they relate to obesity.
The work could help us understand whether managing a child’s weight will make a difference to their executive function.
The team also found waist circumference and waist-to-height ratio, used as a measure of obesity, were similarly associated with reduced executive function. The link to these measures with cortical thickness though was more complicated, with some regions showing reduced thickness while others showed increased thickness.
Professor Paul Fletcher, also of the Department of Psychiatry, added: “This unique and openly available dataset has allowed us to examine the relationships between brain structure, cognitive functions and body weight.
“The links that we observed suggest that there are very real structural brain and cognitive differences in children who are obese. The findings contribute a small part towards our growing understanding of the causes and consequences of obesity in children.”
The Bernard Wolfe Health Neuroscience Fund and Wellcome supported the research, which was published in the journal Cerebral Cortex.