Schools have manned the front lines in the battle against childhood obesity. Through the Healthy, Hunger-Free Kids Act of 2010, First Lady Michelle Obama has promoted low-cal lunches, fresh produce and more. Now, she hopes to ban junk food and soda marketing in schools.
Are these efforts enough to turn the tide? Offering healthy foods and promoting physical activity at school may not be enough to negate the impact of other unhealthy influences in students’ homes and neighborhoods, according to Tracy Richmond, MD, MPH, of Boston Children’s Hospital’s Division of Adolescent Medicine.
Richmond recently published a study in PLOS One that looked at how a school’s physical activity or nutrition resources might influence fifth grade students’ body mass index (BMI).
The study focused on 4,387 students in Birmingham, Ala., Los Angeles and Houston. “We wanted to find out if certain schools look ‘heavier’ because of their composition—meaning that kids at higher risk of obesity, like African American girls or Hispanic boys, cluster within certain schools—or whether something structural in the school influences BMI, like the facilities or programs offered,” explains Richmond.
When the researchers used multi-level statistical modeling to tease out the effects of physical activity programs, nutritional resources and median household income, they found that aggregate household income and girls’ BMI are inversely related. That is, fifth grade girls tend to be heavier in lower-income schools.
The researchers did not observe a similar link among boys, nor did they find connections between average BMI and school factors such as physical education (PE) class time, regular recess schedule, nutrition curriculum and availability of brand-name fast-food items in the cafeteria. The researchers also factored in parents’ BMI.
“Once you accounted for the school composition and parental BMI, there was no variability left,” says Richmond. “The parents and home are so strikingly important [in determining BMI] that schools may not be able to mitigate against those influences.”
One caveat is that there were limitations in the way school programs were measured that could influence the findings. For example, if a school reports daily PE classes, but the students are not active during this time, this would not be accounted for in the PE measure.
Which brings up the question—do schools matter in the anti-obesity effort? Or, as Richmond poses, “Where do schools fit in the hierarchy of families and neighborhoods?”
The answer might be a more comprehensive school effort. The Planet Health curriculum, developed by the Harvard School of Public Health in the 1990s, embeds topics related to healthy diet and physical activity in all school subjects, from math to social studies. Analysis of the program suggested that it helped girls lose weight. “It’s one of the few studies to document change in BMI outcomes,” confirms Richmond.
Now, Richmond and other researchers are taking the next step and studying a prevention effort that includes the Planet Health curriculum plus before-school and after-school programs and environmental changes. Preliminary results are promising, indicating a decline in BMI in participating schools.
As for what’s ahead, Richmond and her colleagues are looking at the influence of schools and neighborhoods in the same study in an effort to understand which one has more influence on health outcomes, including BMI. They hope to guide those developing obesity intervention and prevention programs to target the most effective locations.
