The percentage of adolescents aged 15 to 17 who are
overweight today is about 50 percent higher in families
below the poverty line in comparison to those at or above
it. That difference was not present in the 1970s and 1980s,
according to researchers from the
Johns Hopkins Bloomberg
School of Public Health and other institutions.
The scientists based their analysis on U.S. national
health surveys spanning 33 years. Adolescents aged 15 to 17
who were in families with an income below the poverty line
were more likely to have higher caloric intake from
sweetened beverages, to be physically inactive and to skip
breakfast. Each of these factors may have played a role in
the growing difference in the percentage of overweight
teens associated with family poverty. This trend was
specific to adolescents aged 15 to 17 and was not found
among adolescents aged 12 to 14. The study is published in
the May 24/31 issue of the Journal of the American
Medical Association.
"The prevalence of overweight adolescents in the
United States has more than doubled in the past three
decades. And the percentage of adolescents who are
overweight has increased significantly faster among the
poor in comparison to the nonpoor over the past decade,"
said Richard A. Miech, lead author of the study and an
associate professor in the Bloomberg School's
Department of Mental Health.
The study authors analyzed four U.S. National Health
and Nutrition Examination Surveys: 1971-1974, 1976-1980,
1988-1994 and 1999-2004. Children with a body mass index at
or above the 95th percentile for their age and sex in the
2000 Centers for Disease Control and Prevention growth
charts were classified as overweight. The authors found
that 15-to-17-year-old adolescents with higher daily intake
of calories from sweetened beverages were significantly
more likely to be overweight. In addition, among high
school adolescents, the percentage of daily calories from
drinking sweetened beverages has increased by more than 20
percent over the past decade (from 10.7 percent to 13.2
percent). Sweetened beverage consumption also increased at
a faster rate among poor vs. nonpoor adolescents (67
percent vs. 14 percent). Today, high school adolescents who
live below the poverty line are more likely to be
physically inactive and are also more likely to skip
breakfast — two behaviors associated with excessive
weight gain. The researchers did not see this same trend in
adolescents aged 12 to 14; in this age range, however,
nonpoor black adolescents were more likely to be
overweight than their poor counterparts.
The researchers note that as more and more adolescents
gain excessive weight, the associated consequences —
type 2 diabetes, hypertension, sleep apnea, poor quality of
life and morbidity in adulthood — will also
increase.
"I believe that the trend in poverty and adolescent
obesity can be reversed if there is sustained public will
to do so. While there is no silver bullet that will end
this trend or the obesity epidemic in general, we know many
of the major factors involved, and we are beginning to do
something about them," Miech said. "The recent, voluntary
withdrawal of soft drinks from schools is a good step. We
need to further develop and implement additional programs
to improve adolescent nutrition and physical exercise,
especially among the poor."
Study authors include Miech, Shiriki K. Kumanyika,
Nicolas Stettler, Bruce G. Link, Jo C. Phelan and Virginia
W. Chang.
The authors were supported by grants from the National
Institutes of Health, the National Center for Minority
Health and Health Disparities and the Robert Wood Johnson
Foundation Health Policy Investigator Award.
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