June 14, 2012 -- Childhood obesity affects math performance in school, along with child's social skills and well being, according to a new study published in the journal Child Development.
Researchers from the University of Missouri analyzed data of more than 6,000 children in the Early Childhood Longitudinal Study-Kindergarten Cohort, which collected information from children starting in kindergarten and following them through the fifth grade. At five different times, parents reported family dynamics and teachers reported on the children's social skills and emotional well-being. Researchers tested the children on academics, and recorded their height and weight.
Kids who were obese throughout the study period performed worse on math tests in the first through fifth grades than children who were not obese.
"Obesity that persists across the elementary school years has the potential to compromise several areas of children's development, including their social and emotional well-being and academic performance," said Sara Gable, associate professor of nutrition and exercise physiology at University of Missouri and lead author of the study.
In addition to the math performance findings, obese children reportedly felt sadder, lonelier and more anxious than kids of healthier weights. Researchers said this emotional well being also could contribute to their poorer performances in math.
Obesity among children continues to grow in the U.S.; 17 percent, or about 12.5 million, children and teens are obese, according to the Centers for Disease Control and Prevention. Since 1980, obesity among the youth population has nearly tripled. One in seven low-income pre-school children is obese.
While weight may indeed contribute to poor school performance, there are likely several confounding factors that also contribute to an obese child's overall well-being, experts said.
"Obesity does not prevent kids from doing math, but obesity develops in families where there may be less oversight, less education, fewer resources," said Dr. David Katz, director of the Yale Prevention Center.
While a link between obesity and poor school performance has been established in the past, this study analyzes the connection between the timing of the obesity onset and factors including weight, behavior, relationships and academic performance.
The research looks to fill in the blank space that connects the weight dot to the academic performance dot, said Katz.
"Stress has been shown to affect brain development and functioning," Dr. Jennifer Cross, a pediatrician at the Komansky Center for Children's Health at NY-Presbyterian/Weill Cornell Medical Center, wrote in an email. "If obesity causes a child to feel chronically stressed (i.e. bullying, low self esteem, etc.), that could lead to differences in the brain."
While it is difficult to say whether obesity actually affects cognition, "we certainly can say that obesity affects everything from self-esteem to social standing to mood and even hormonal balance, so the likelihood that there would be a whole cascade of effects between weight and math test scores is very high," said Katz.