And, while we re on the topic of obesity, children s obesity is getting some attention today, too. Unfortunately, it s for the wrong reasons. A study just published in Pediatrics has concluded that strict laws in some states restricting school sales of junk food and sweetened drinks may contribute to lowering childhood obesity rates. The study results are making headlines, but its design is drawing skepticism from experts.
In order to examine the impact of laws regulating the nutritional content of foods and beverages sold outside of federal school meal programs, researchers led by a health policy specialist from the University of Illinois, Chicago, classified such laws in 40 states as either strong, weak, or non-existent in 2003 and then again in 2006. They then looked at objective height and weight data from 6,300 students in those states, first in fifth grade and again in eighth grade. Finally, taking into account race, gender, income, and school location, the researchers estimated the association between the strictness of the nutritional requirements of these laws and changes in student BMI status over the course of the three-year study period.
By means of these methods, the researchers concluded that such laws could make a difference in student obesity levels. They found that students exposed to strong laws to begin with gained, on average, 0.25 fewer BMI units and were less likely to remain overweight or obese than students in states with no laws. For instance, in states with consistently strong laws in elementary and middle school, the rate of obesity fell from 39 percent to 34 percent from fifth grade to the end of eighth grade. Lead author Dr. Daniel R. Tabor emphasizes that, to have a significant impact, these laws must be comprehensive, contain strong language, and [be] enacted across grade levels.
But several experts are not entirely convinced. Boston University statistician Dr. Mark Glickman, for instance, believes that the study s design makes it difficult to draw any convincing conclusions. He points out the paradoxical finding that the states with the highest levels of obesity had some of the strongest laws. And while Dr. David Ludwig, an obesity specialist at Harvard Medical School, praised the researchers for taking on a topic that s so complicated, he was quick to add that there are a great many factors that coalesce to influence body weight. Disentangling these influences and looking at the independent effects of just one is a methodological nightmare."
ACSH's Dr. Gilbert Ross agrees with Drs. Glickman and Ludwig. The study design is ultimately too amorphous, using imprecise parameters to classify the laws and drawing conclusions based on correlation alone. Further, using entire states for such an analysis cannot possibly yield relevant data on such a complex topic. However, that doesn t stop the media from paying it a lot of attention: People are always looking for simple solutions through regulations and laws when it comes to the high rate of obesity.