Childhood Obesity Rates Rise in Summer Holidays, Not School Year

Marlene Busko

November 10, 2016

NEW ORLEANS — From kindergarten through grade 2, the prevalence of overweight and obesity increases in American children — but only during summer vacations, not during the school year, according to a new study presented at Obesity Week 2016 and simultaneously published in Obesity.

During the school months in each of the 3 school years studied, there was a significant, slight decline in rates of obese children and a nonsignificant slight reduction in rates of overweight children, which suggests that school policies aimed at reducing childhood obesity — such as increasing physical activity, providing healthy lunches, or banning soda — may be protective.

But the research highlights the need to look beyond the school year, stressed lead author Paul T von Hippel, PhD, associate professor of public affairs at the LBJ School of Public Affairs, University of Texas, in Austin.

"This is not to say that school-based policies can't be effective, but we need to [also] think about trying to change children's behavior when they are not in school," he urged. "We need to educate parents about nutrition, reduce child screen time, and regulate food marketing and advertising" aimed at children.

Sending more children to summer camps or learning programs, for example, could potentially help lower rates of childhood obesity, he suggested.

"My own experience with childhood obesity ended when I went to [a theater-arts] camp at age 8," he related.

"The message for practitioners is, you need to talk to the parents. If they have a child at risk, they need to know that the summer months may be an especially at-risk time," session comoderator Donna H Ryan, MD, professor emeritus at Pennington Biomedical Research Center, in Baton Rouge, Louisiana, and associate editor in chief of Obesity, told Medscape Medical News.

Are Schools to Blame for Childhood Obesity?

Dr von Hippel explained that it is important to pinpoint whether causes of childhood obesity lie mainly within schools (fewer gym classes, too much nonnutritious food) or outside schools, so that more targeted policies to tackle the problem can be developed.

"If obesity originates primarily inside schools, then we may hope to substantially reduce obesity through policies affecting school meals, competitive foods, physical education, and other programs affecting the school environment," he and coauthor Joseph Workman, PhD, a sociologist and postdoctoral research fellow at Nuffield College, University of Oxford, United Kingdom, say in their paper.

"But if obesity originates primarily outside of schools, then school-based programs must try to shape out-of-school behaviors, and we must further emphasize out-of-school interventions to reduce screen time, limit child-directed food marketing, promote out-of-school activities such as summer school and summer camp, and educate parents about nutrition."

Muddying the waters is conflicting data — some studies have reported an increase in body mass index (BMI) rates in children in summer months, while others found no increase.

Home Environment Must Be Addressed to Tackle Obesity Epidemic

To investigate this issue further, the researchers analyzed data from a nationally representative sample of 5- to 7-year-olds who entered kindergarten in 2010 to 2011 and were weighed and measured at the beginning and end of kindergarten, grade 1, and grade 2.

They had complete data from the Early Childhood Longitudinal Study, Class of 2010–2011 for 13,006 children in 846 public and private schools.

From the beginning of kindergarten until the end of grade 2, the prevalence of obesity increased from 8.9% to 11.5%, but the rates increased only between the end of one school year and the beginning of the next.

Similarly, during these first 3 years of school, the prevalence of overweight rose from 23.3% to 28.7%, with rates increased only during summer vacation.

They did not find any differences in rate of BMI increase between African American, Hispanic, or white children.

"Schools are certainly doing some things to reduce children's vulnerability to weight gain," Dr von Hippel said. But "it appears that we can't just hope that schools can make up for what's happening outside.

"Educators have long worried that summer break leads to knowledge loss, and now we know that it is also a time of excessive weight gain for our youngest schoolchildren," he noted.

"Our findings raise questions for parents and policymakers about how to help children adopt healthy behaviors during the long summer vacation to stop unhealthy weight gain. Our results also suggest that we cannot reverse the obesity epidemic if we focus only on what children are doing and eating while they are in school," he concluded.

Amanda Staiano, PhD, Pennington Biomedical Research Center, and a spokesperson for the Obesity Society and assistant professor at Louisiana State University, Baton Rouge, said: "Now that we have solid data pointing to summer vacation as a time for potential weight gain in young children, the next step is to work together to shape out-of-school behaviors.

"Parents can take some simple steps to help their children like sticking to a school-year sleep schedule and reducing screen time," she notes in an Obesity Society press release.

The study was supported by a grant from the Russell Sage Foundation. The authors have no relevant financial relationships.

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Obesity. 2016;24:2296-2300. Article


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