Obesity rates declining, but not in all adolescent groups

Madsen KA. Pediatrics. 2010;126:434-442.

Although the prevalence of high BMI has recently declined in children and adolescents, disparities in BMI are still observed in several racial/ethnic groups, particularly black and American Indian girls.

Researchers examined data on more than 8,000 fifth-, seventh- and ninth-grade students who underwent school-based BMI screening in California from 2001 to 2008. High BMI cut points used were the 85th, 95th 97th and 99th percentiles or higher.

When the researchers examined the prevalence of high BMI among girls, they found:

Black and American Indian girls had increases in three of the four BMI cut points.
Hispanic girls experienced an increase followed by a plateau after 2005.
White girls’ prevalence increased from 2001 to 2005 before declining to 2001 rates.
Asian girls experienced no change.

Disparities were also observed in boys:

White boys experienced an increase through 2005 following by a decline to 2001 for all cut points.
Hispanic and Asian boys’ levels declined after 2005 for the three lowest BMI cut points but levels remained greater than 2001 levels.
American Indian boys had a decline in only the 95th percentile cut point after 2007.

No declines were observed in children of any racial/ethnic group with a BMI cut point of the 99th percentile or greater. According to 2008 screening results, children with the 99th percentile or greater BMI cut point had the greatest disparities in prevalence (4.9% for American Indian girls and 4.6% for black girls vs. 1.3% for non-Hispanic white girls).

“To our knowledge, this is the first study to document a population-based decline in prevalence of high BMI after 2005, among most boys and for white girls,” the researchers wrote. However, “the encouraging first signs of a decline in the obesity epidemic are tempered by concerns about increasing disparities.”

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