Socioeconomic factors influence effectiveness of school food policies

Chips, soda, chocolate, candy -- while these high-calorie treats are not part of a healthy diet, for years they were sold at California public elementary schools with no government restrictions. Students gobbled them up, and, at the same time, obesity levels rose.

Emma V. Sanchez-Vaznaugh

Associate Professor in the Department of Health Education Emma V. Sanchez-Vaznaugh

That changed 11 years ago, when the state enacted policies limiting the so-called “competitive” food and beverages (CF&B) that could be sold at schools outside of school meal programs. According to new research, these policies may have helped lower childhood obesity rates in elementary schools, but their effectiveness is not universally consistent: Obesity rates among students attending schools in disadvantaged neighborhoods showed less improvement than their peers at schools in wealthier neighborhoods.

"The good news is that for all kids, regardless of where their schools are located, the trends in obesity improved -- though the rates are still pretty high," said Emma V. Sanchez-Vaznaugh, an associate professor in the Department of Health Education at San Francisco State University and lead author of the study. "However, the bottom line is that everyone benefitted, but not equally."

In 2004, California put into effect some of the nation's most comprehensive policies limiting CF&B sales aimed at K-8 students, targeting sugar-sweetened beverages, fat, portion size and calories from fat. Sanchez-Vaznaugh's study, published online in JAMA Pediatrics today, compared overweight/obesity prevalence trends before and after these policies were implemented to determine whether these trends differed depending on socioeconomic factors in school neighborhoods. The study was based on data for more than 2.7 million fifth-grade students in 5,362 California public schools from 2001 to 2010.

Sanchez-Vaznaugh and her coauthors found that, from 2005 to 2010, childhood obesity rates leveled off among students attending schools in socioeconomically disadvantaged neighborhoods. But in more wealthy neighborhoods, there were significant improvements, with obesity rates dropping as much as 1.2 percent for females and one percent for males.

While these findings suggest that the CF&B restrictions are crucial tools to prevent and reduce childhood obesity, the extent of their effectiveness could depend on socioeconomic and other factors in school neighborhoods, Sanchez-Vaznaugh said. Research has shown that children in disadvantaged neighborhoods are exposed to environmental factors that could make them more susceptible to obesity, she explained. Children in disadvantaged neighborhoods may be negatively affected, for example, by exposure to unhealthful food sources, such as fast food outlets and convenience stores. They also may not have as many opportunities for physical activity if their neighborhoods have fewer parks and heavier traffic.

"Children attending schools in disadvantaged neighborhoods have many more obstacles to healthy eating and active living," Sanchez-Vaznaugh said. "It's very important to consider what else can be done."

"Association between competitive food and beverage policies in elementary schools and childhood overweight/obesity trends — differences by neighborhood socioeconomic resources" was authored by Emma V. Sanchez-Vaznaugh; Brisa N. Sanchez of the University of Michigan, Ann Arbor; Patricia B. Crawford of the University of California, Berkeley; and Susan Egerter of the University of California, San Francisco. The study was published online in JAMA Pediatrics (a journal of the American Medical Association) on May 4.

-- Beth Tagawa