National study examines ways federal policy can impact childhood, adolescent obesity

Brown School researcher helps find that beverage tax, exercise promotion best long-term options

A tax on sugar-sweetened beverages such as sodas, energy drinks, sweet teas and sports drinks could reduce obesity in adolescents, and exercise promotion, such as after-school physical activity programs, could impact younger children in the fight against fat.


Those are the findings of a new national study co-authored by Ross Brownson, PhD, professor at the Brown School and School of Medicine at Washington University in St. Louis and scholar in the Institute for Public Health.

The study, “Reducing Childhood Obesity Through U.S. Federal Policy: A Microsimulation Analysis,” was conducted by Brownson and partners from seven other institutions, and appears in the online Aug. 27 edition of the American Journal of Preventive Medicine. The Partnership for Prevention led the effort, with Brownson chairing the working group.

Although recent data suggest that childhood obesity has plateaued or begun to decline, its prevalence remains high in the United States, especially among racial and ethnic minorities and low-income populations. In 2009–2010, nearly one in three U.S. youth aged 2–19 years were either overweight or obese, and 17 percent were obese.

Brownson, who also is director of the university’s Prevention Research Center, and his co-authors set out to determine the effectiveness of three federal policies aimed at reducing childhood obesity: afterschool physical activity programs, a one cent per ounce sugar-sweetened beverage excise tax, and a ban on fast food television advertising to children under 12.

For each policy, literature was reviewed from January 2000-July 2012 to find evidence of effectiveness and to create average effect sizes. The investigators then used a Markov microsimulation model to estimate each policy’s impact on diet or physical activity, and then Body Mass Index (BMI), in a simulated school-aged population in 2032, or 20 years after implementation.

The model predicted that all three policies could reduce the prevalence of childhood obesity, particularly among blacks and Hispanics, who have higher rates of obesity than whites, thus demonstrating that federal policy could alter the childhood obesity epidemic.

However, the researchers found the excise tax to be the best option, and predicted that by 2032 it could reduce obesity among adolescents ages 13-18 by 2.4 percent. The tax would have an added bonus, the study said, of generating revenue for additional obesity prevention programs.

Afterschool physical activity programs would reduce obesity the most among children ages 6-12 (1.8 percentage points) and the advertising ban would reduce obesity the least (0.9 percentage points).

“This study clearly illustrates the power of prevention policy in addressing one of our most pressing public health issues,” Brownson said. “We anticipate that our findings will inform federal policy as national leaders plan efforts to address childhood obesity.”