Study finds soda pop sales tied to obesity in Allegheny County
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If Allegheny County added a tax of 1 cent per ounce on sugary soft drinks, it would cut consumption up to 8 percent. It would also produce an extra $54 million in revenue that could be plowed back into anti-obesity efforts.
That's the conclusion reached by 21 undergraduate students at Carnegie Mellon University, mostly seniors in the departments of Engineering and Public Policy or Social and Decision Sciences.
The students spent the entire fall semester of 2009 producing a "lifestyle analysis" of the obesity problem in the county, where 28.4 percent of the population is grossly overweight, even worse than the national average of 26.7 percent. That, in turn, leads to a less healthy populace with lower productivity and higher medical costs.
The county already taxes soft drinks at 6 percent. In March, Mayor Luke Ravenstahl proposed an added tax of 2 cents per ounce on sugary drinks, in line with a plan of his counterpart in Philadelphia. The beverage industry opposes a tax hike.
The CMU students looked at obesity from five angles -- food shopping, school programs, restaurant menus, workplace initiatives and recreational facilities -- to see what role each played in obesity and what changes would have a positive impact.
The results were unveiled in a 142-page booklet this week, four months after the students presented their findings to a review panel including representatives of Highmark, the Pittsburgh Public Schools, the YMCA of Greater Pittsburgh and Giant Eagle, in hopes that they will act on some of the findings. (The document will not be posted online because the university does not want anyone mistaking it for an official, peer-reviewed CMU report, but those interested in obtaining a copy can call 412-268-2670.)
The paper notes that Americans drink 14 billion gallons of soda pop each year. Based on average consumption, that extrapolates to 57 million gallons for Allegheny County.
The researchers found a clear correlation between the high-sugar soda pop sold in grocery stores and the obesity rates at schools in the surrounding area.
Using cash register data, they found that schools located near stores that sold the most soda had more overweight students. Schools had fewer overweight students when nearby stores sold more fruits and vegetables -- fresh, frozen and canned.
However, the correlation was much lower between school obesity rates and sales of high-fat, high-sugar foods. Specific schools were not named in relation to obesity.
The final report had some other surprises, said Marvin Sirbu, who supervised the study along with Ed Rubin, both of the Engineering and Public Policy department.
"We had expected a significant relation between the availability of parks and the obesity rate in surrounding schools," said Dr. Sirbu. What they found instead was that, when controlling for income, parks have no effect.
"Income is the real predictor," he said. Wealthy communities have more parks, and wealthier people also have a lower incidence of obesity.
Still, the paper recommends building more playgrounds, basketballs courts and the like because, he said, "this is not a definitive analysis. Other studies say parks do correlate to obesity, but they have to be close enough for people to walk to them."
Dr. Sirbu was also surprised by how many places had zero parks or basketball courts (49 townships in the county and nine neighborhoods in Pittsburgh) and by how few minutes of actual exercise students get in school, regardless of income. The students looked at four districts across the economic spectrum and found students get 40 to 70 minutes of exercise per week. The districts were not named in the report.
"The schools are doing almost nothing to promote physical education," Dr. Sirbu said. "That was pretty shocking."
Many of the project's recommendations are things that have been noted previously by a host of interested parties: better labeling of healthful food in grocery stores and on restaurant menus, more nutritional school lunches, more time spent on rigorous physical activity in gym class, more community parks and playgrounds, more workplace incentives to eat better and exercise more.
"There are simple steps for reducing obesity, but it's a problem that takes a variety of efforts, not just one solution," said Sharon Wagner, a Ph.D. candidate who served as a graduate adviser on the project.
She said the students were highly enthusiastic from the first day of the study.
"It seemed like a problem that hit close to home for people," she said.
"This had a double benefit. It helped the students learn what a good research project looks like and what real analysis is, while doing something useful and important for the community."
Lydia Remington, a senior from Fairfax, Va., who plans to go on for a master's degree in public health, worked on the eating-at-home segment of the project.
Her group created an online survey that was filled out by several thousand people based on their body mass index (weight in relation to height), what choices they made in the store and what they were willing to buy. They also met with Giant Eagle marketing personnel, who she said were "very helpful and receptive."
"What surprised me most was even though people were educated about healthy options, they didn't follow through with eating that way," Ms. Remington said.
"Awareness is not enough. We tried to find ways to motivate people to lose weight. People don't always read the ingredients, so stores could have indicators in the aisles to show healthy options with an apple or a heart sign. Or they could have a nutritionist on site to help people make good choices."
First Published May 6, 2010 12:00 am