Amid all the talk and new initiatives aimed at combating youth obesity, there’s been a trickle of evidence that obesity is declining among certain youth populations. One question is whether anti-obesity measures have anything to do with it.
The latest data come from California, where researchers looked at body mass index (BMI) readings, taken at schools, for eight million youths from 2001 to 2008. The study from the University of California/San Francisco – Disparities in Peaks, Plateaus and Declines in Prevalence of High BMI Among Adolescents – found overall BMI levels increasing from 2001 to 2005, then declining to 2008 for whites and Asians, rising for black females and leveling off for Hispanics.
That latter time period is significant, because in 2005 California lawmakers banned the sale of soft drinks and unhealthy snacks at public schools. Some wonder if that might have contributed to the BMI decline among some groups of youths – a question that’s germane to youth organizations, many of which have reduced or banned the sale of junk food at their facilities.
Kristine Madsen, the lead researcher on the University of California report published in Pediatrics last week, thinks the California law contributed to a decline in youth obesity, while noting that most of the schools did not implement the soft drink and snack ban immediately.
“I think the awareness [of childhood obesity] has greatly increased, particularly in this last decade, and that was the time when many pieces of legislation were imposed to change the environment in schools,” Madsen said. “We think that there’s good reason to believe that these environmental changes can have a significant impact on the obesity epidemic.”
One cause of concern voiced the researchers: The heaviest youths showed the largest increases in obesity rates. Those with BMIs in the 99th percentile or higher when the study concluded (designated as “severely obese”) showed the greatest increase in BMI over the study period.
James Marks, senior vice president of the Robert Wood Johnson Foundation – where he directs the foundation’s $500 million efforts to combat childhood obesity – described the California findings as exciting, particularly because the study had the largest sample size he’s seen in any youth obesity research.
But Marks was discouraged by the racial disparity and the BMI increase among the severely obese. “The optimism of seeing some decline has to be tempered by the concern that it’s not reaching everyone,” he said.
Evidence from elsewhere
The declines in California complement similar statistics from the most recent federal figures on pediatric obesity from the National Health and Nutrition Examination Survey (NHANES), considered the most reputable source for following obesity trends.
Based on interviews and physical examination figures from doctors’ offices around the nation, the annual NHANES found a leveling off of overall youth obesity from 1999 to 2008. For 2007-08, the data showed that 13.3 percent of 6-to-19-year-olds had a BMI in the 97th percentile or higher, 18.7 percent were in the 95th percentile or higher and 34.7 percent were in the 85th percentile or higher. Those figures matched or were close to the same measurements in the California study. NHANES also showed higher obesity rates among Hispanic and black youth than among whites.
And earlier this summer, a study funded by the National Institutes of Health showed declining percentages of obese and overweight youths at 42 surveyed middle schools around the country. Interestingly, the study – A School-Based Intervention for Diabetes Risk Reduction, published in the New England Journal of Medicine – showed no difference in the declining obesity rates of students placed in the intervention schools compared with those in the control group. The intervention schools gave students a nutrition education curriculum and increased physical activity. The study makes no mention of banning the availability of sodas and snacks in the schools, as California did.
Madsen, of the California study, has a few recommendations on improving youth fitness and nutrition.
“We certainly hope that there will be changes to school policies, including increased PE [physical education] time and improved nutritional standards,” she said. “We need to increase reimbursement for publicly funded school meals so they can offer fresh fruits and vegetables.” She also suggested regulating the advertisements of unhealthy foods targeted to children and turning California’s ban of soft drinks and unhealthy snacks at public schools into national policy.
Marks agreed with the latter recommendation, saying that the California school regulations were probably one factor behind what that study found, but said a lot more needs to be done. He suggested increased physical activity when youth are away from school, eliminating “food deserts” (poor communities that lack access to fresh and healthy foods) and regulating food prices, noting that the cost of fresh fruits and vegetables has been increasing at a higher rate than sugary and fattening foods.
Proposed policy changes might get a further boost from another recent report on obesity, this one a national poll in which adults were asked about the major problems facing U.S. children. The University of Michigan C.S. Mott Children’s Hospital poll showed that childhood obesity received the most votes of the 20 issues listed, with 38 percent of the more than 2,000 participants naming it as a big problem. Drug addiction and nicotine addiction followed with 30 percent and 29 percent of the votes, respectively.