Childhood obesity rates in California are showing signs of leveling off or even declining among some adolescents, a new study led by researchers at the University of California, San Francisco has found.
But the rates continue to climb for some ethnic groups, and the worst cases are as numerous, and as serious, as ever.
The study, published online Monday in the journal Pediatrics, was the first to find differences in obesity trends over time by race and ethnicity, according to the authors.
Kristine Madsen, an assistant professor of pediatrics at UCSF who has medical and public health degrees, and colleagues examined the body mass index of adolescents in California from 2001 through 2008. The data for 8 million fifth-, seventh- and ninth-graders were available from records kept as part of school fitness exams.
The study found that obesity rates among white and Asian girls and boys peaked in 2005, then dropped through 2008. Rates for Hispanic children also peaked that year and then leveled off, even as obesity rates for Hispanic boys declined. Rates among African-American boys were stable through the entire period.
Obesity rates for black and American Indian girls climbed throughout the period, and these groups were more than three times as likely as white girls to be severely obese.
When comparing groups at the 99th percentile of body mass index — severely obese — only Asian youth and white boys showed any signs of decline after 2005. All other groups – including Hispanic boys and girls, white girls, black boys and girls, and American Indian boys and girls – peaked in 2005 and then remained at a plateau through 2008.
“When you look at the very heaviest end of the spectrum, the picture is pretty bleak, and we do not yet know if severe obesity rates for these groups will remain at a plateau or continue to increase,” Madsen added.
While the results suggest that anti-obesity campaigns are having an effect, Madsen said more change is needed at home, at school and in after-school gathering places to encourage healthier eating habits and reduce food consumption.
“While the decline and stabilization of obesity among certain groups is encouraging, we are seeing an increase in disparities that is troubling, especially among the most severely obese youth,” Madsen said. “As our country becomes increasingly diverse, it is critical that we act quickly to address these disparities.”