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Obesity Rates Decline For Many
Adolescents, But Disparities Worsen
Although obesity rates have started to decline and
level off for many adolescents, they continue to
increase for certain racial and ethnic minorities,
according to a new University of California,
San Fransisco (UCSF) led study.
The evidence of increasing racial disparities for obesity
underscores the need for more tailored intervention programs
and policies that target high-risk groups, the authors conclude.
The study, which is the first to find significant differences in
obesity trends over time by race and ethnicity, appears online
in the journal Pediatrics. It also will be published in the
September 2010 issue of the journal.
“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,” said first author Kristine Madsen, MD, MPH, an assistant
professor of pediatrics at UCSF. “As our country becomes
increasingly diverse, it is critical that we act quickly to address
these disparities.”
The researchers examined trends in the prevalence of high
body mass index (BMI) among Hispanic, non-Hispanic white,
Asian, black, and American Indian adolescents in California
from 2001 through 2008. BMI is a measure of body fat based
on a person’s height and weight that is commonly used to screen
for obesity. Generally, children are considered obese if they have
a BMI at or above the 95th percentile, and severely obese if their
BMI score is at or above the 99th percentile.
The data revealed that obesity rates at the 95th percentile
declined or stabilized among a number of groups during the
time period studied. Among white and Asian girls and boys,
obesity rates peaked in 2005, then declined over the next three
years, with 2008 rates coming in at 12 percent for white youth
and 13 percent for Asians. Overall rates for Hispanic youth also
peaked in 2005 and then leveled off at 26 percent through 2008;
although Hispanic boys did show a small decline on their own.
Rates among black boys stayed at the same level each year.
However, from 2001 through 2008, the prevalence of obesity
continued to climb for black and American Indian girls, reaching
22 percent and 23 percent, respectively. Furthermore, these two
groups were more than three times as likely as white girls to be
severely obese, with a BMI at the 99th percentile.
When comparing groups at the 99th BMI percentile, the
researchers found that 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,” the researchers said.
The researchers analyzed the health records of more than eight
million fifth, seventh, and ninth-grade students in California who
underwent the state’s mandatory school-based BMI screening.
Among the students studied, 46.4 percent were Hispanic, 32.8
percent were white, 12.6 percent were Asian, 7.7 percent were
black, and 0.5 percent were American Indian.
According to the researchers, the study’s large and highly diverse
group of subjects is a unique strength. And, although the data
were confined to one state, the results show population level
trends that are applicable elsewhere, since about one in eight
children in the United States currently live in California.
“We need to focus on implementing real change in the places
where kids spend most of their time... at home, at school and
in the after-school arena, to encourage healthier habits and
reduce consumption,” they said. “Priorities must be reconsidered
so that health is not an afterthought.”
The research was supported by grants from the Robert Wood
Johnson Foundation, the Eunice Kennedy Shriver National
Institute of Child Health and Human Development, and the
American Heart Association.
Story Source: University of California - San Francisco
Journal Reference:” Disparities in Peaks, Plateaus, and Declines
in Prevalence of High BMI Among Adolescents” Pediatrics, 2010;
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