Study shows link between morbid obesity, low IQ in toddlers

August 30, 2006

University of Florida researchers have discovered a link between morbid obesity in toddlers and lower IQ scores, cognitive delays and brain lesions similar to those seen in Alzheimer’s disease patients, a new study shows.

Although the cause of these cognitive impairments is still unknown, UF researchers suspect the metabolic disturbances obesity causes could be taking a toll on young brains, which are still developing and not fully protected, they write in an article published in the Journal of Pediatrics this month.

“It’s well-known that obesity is associated with a number of other medical problems, such as diabetes, hypertension and elevated cholesterol,” said Dr. Daniel J. Driscoll, a UF professor of molecular genetics and microbiology in the College of Medicine and the lead author of the study. “Now, we’re postulating that early-onset morbid obesity and these metabolic, biochemical problems can also lead to cognitive impairment.”

Researchers compared 18 children and adults with early-onset morbid obesity, which means they weighed at least 150 percent of their ideal body weight before they were 4, with 19 children and adults with Prader-Willi syndrome, and with 24 of their normal-weight siblings. Researchers chose lean siblings as a control group “because they share a socioeconomic group and genetic background,” Driscoll said.

The links between cognitive impairments and Prader-Willi syndrome, a genetic disorder that causes people to eat nonstop and become morbidly obese at a very young age if not supervised, are well-established. But researchers were surprised to find that children and adults who had become obese as toddlers for no known genetic reason fared almost as poorly on IQ and achievement tests as Prader-Willi patients. Prader-Willi patients had an average IQ of 63 and patients with early-onset morbid obesity had an average of 78. The control group of siblings had an average IQ of 106, which falls within the range of what is considered normal intelligence.

“It was surprising to find that they had an average IQ score of 78, whereas their control siblings were 106,” Driscoll said. “We feel this may be another complication of obesity that may not be reversible, so it’s very important to watch what children eat even from a very young age. It’s not just setting them up for problems later on, it could affect their learning potential now.”

While performing head MRI scans of subjects, researchers also discovered white-matter lesions on the brains of many of the Prader-Willi and early-onset morbidly obese patients. White-matter lesions are typically found on the brains of adults who have developed Alzheimer’s disease or in children with untreated phenylketonuria, the researchers wrote.

These lesions could be affecting food-seeking centers of the brain, causing the children to feel hungrier. But they are most likely a result of metabolic changes that damage the young, developing brain, Driscoll said.

More studies are needed to understand what is causing these cognitive impairments, said Dr. Merlin Butler, a professor of pediatrics at the University of Missouri and chief of genetics and molecular medicine at Children’s Mercy Hospital and Clinics.

“This could be a really significant observation,” Butler said. “It’s an interesting concept. It’s a whole new area of investigation.”

The findings are preliminary and additional studies are planned, Driscoll said. Dr. Jennifer Miller, a UF assistant professor of pediatric endocrinology and the first author of the study, and other researchers from UF, All Children’s Hospital in St. Petersburg, Fla., and Baylor College of Medicine also took part in the research.

Although there is no known genetic cause for early-onset morbid obesity, Driscoll said there are likely genetic and hormonal factors at play that researchers have yet to discover, particularly since these children are becoming obese at a time when their parents still control what they eat. The researchers studied several sets of fraternal twins where one twin was lean and the other morbidly obese, yet their parents reported that each ate the same amount of food. In one case, the obese child actually ate less, Driscoll said.

Driscoll is also careful to point out that adults or children who become obese later in childhood are not at-risk for these cognitive impairments because their brains are sufficiently developed to fend off damage from obesity.

“We’re all mindful that this is an obese society,” he said. “We all need to be more careful with respect to what we eat, but in particular, that’s very important for children under 4.”

Source: University of Florida

Explore further: Obesity and overweight multiply the risk of cancer and heart disease

Related Stories

Obesity and overweight multiply the risk of cancer and heart disease

January 17, 2018
Being overweight or obese exponentially increases the risk of suffering heart disease or cancer. This is the conclusion of the Spanish Risk Function of Coronary and Other Events (FRESCO) study led by researchers from the ...

Physical activity impacts child growth, new study finds

January 17, 2018
Scientific Reports has just published an important new study by Hunter post-doctoral research fellow Samuel Urlacher. Funded by the National Science Foundation, Dr. Urlacher is a biological anthropologist whose research seeks ...

Home visit program can help prevent toddler obesity

January 16, 2018
(HealthDay)—The "Minding the Baby" (MTB) parenting home visiting program can significantly lower rates of obesity in young children, according to a study published online Jan. 16 in Pediatrics.

Teens likely to crave junk food after watching TV ads

January 15, 2018
Teenagers who watch more than three hours of commercial TV a day are more likely to eat hundreds of extra junk food snacks, according to a report by Cancer Research UK.

Statins are safe for children with abnormal cholesterol levels

January 16, 2018
The charity says the findings will 'reassure' parents of children with familial hypercholesterolaemia (FH) – an inherited condition that significantly increases the risk of a heart attack in their 40s, 30s or even 20s.

Adult leukaemia can be caused by gene implicated in breast cancer and obesity

January 16, 2018
When people think of leukaemia, they usually think of blood cancers that affect children. These mostly come under the category of acute lymphoblastic leukaemia – or ALL – and are different to the group of blood cancers ...

Recommended for you

Researchers illustrate how muscle growth inhibitor is activated, could aid in treating ALS

January 19, 2018
Researchers at the University of Cincinnati (UC) College of Medicine are part of an international team that has identified how the inactive or latent form of GDF8, a signaling protein also known as myostatin responsible for ...

Investigators eye new target for treating movement disorders

January 19, 2018
Blocking a nerve-cell receptor in part of the brain that coordinates movement could improve the treatment of Parkinson's disease, dyskinesia and other movement disorders, researchers at Vanderbilt University have reported.

Intensive behavior therapy no better than conventional support in treating teenagers with antisocial behavior

January 19, 2018
Research led by UCL has found that intensive and costly multisystemic therapy is no better than conventional therapy in treating teenagers with moderate to severe antisocial behaviour.

Women run faster after taking newly developed supplement, study finds

January 19, 2018
A new study found that women who took a specially prepared blend of minerals and nutrients for a month saw their 3-mile run times drop by almost a minute.

Study ends debate over role of steroids in treating septic shock

January 19, 2018
The results from the largest ever study of septic shock could improve treatment for critically ill patients and save health systems worldwide hundreds of millions of dollars each year.

Rocky start for Alzheimer's drug research in 2018

January 19, 2018
The year 2018, barely underway, has already dealt a series of disheartening blows to the quest for an Alzheimer's cure.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.