The U.S. obesity prevalence increased from 13 percent to 32
percent between the
1960s and 2004, according to researchers at the Johns Hopkins Bloomberg
School
of Public Health
Center for Human Nutrition. The prevalence of obesity
and
overweight have increased at an average rate of 0.3Ð0.8
percentage points across
different sociodemographic groups over the three decades.
Some minority and low
socioeconomic status groups are disproportionately
affected, among them non-
Hispanic black women and children; Mexican-American women
and children; low
socioeconomic status black men, white women and white
children; Native
Americans; and Pacific Islanders. The meta-analysis was
published online May 17
in advance of the 2007 issue of the journal Epidemiologic
Reviews.
"The obesity rate in the United States has increased
at an alarming rate
over the past three decades. We set out to estimate the
average annual increase
in prevalence as well as the variation between population
groups to predict the
future situation regarding obesity and overweight among
U.S. adults and
children," said Youfa Wang, lead author of the study and an
assistant professor
in the Bloomberg School's
Department of International Health. "Obesity is a
public health crisis. If the rate of obesity and overweight
continues at this
pace, by 2015, 75 percent of adults and nearly 24 percent
of U.S. children and
adolescents will be overweight or obese."
The study authors included in their meta-analysis 20
journal papers,
reports and online data sets. In addition, data from four
national surveys —
NHANES, BRFSS, Youth Risk Behavior Surveillance System and
National Longitudinal
Survey of Adolescent Health — were included in order
to examine the disparities in
obesity. The authors defined adult overweight and obesity
using body mass index
cutoffs of 25 and 30, respectively. Children at risk for
overweight and who were
overweight were classified as being in the 85th and 95th
percentiles of body
mass index, respectively. (Note: Unlike definitions for
adults, the Centers for
Disease Control and Prevention uses "overweight" to refer
to the highest body
mass index for children and adolescents. Therefore, it is
inaccurate to use the
term "obese" when referring to elevated body mass index in
this age group.)
Among the key findings:
66 percent of U.S. adults were
overweight or obese in 2003Ð2004.
Women 20 to 34 years old had the
fastest increase rate of obesity and
overweight.
80 percent of black women ages 40
or older are overweight; 50 percent are
obese.
Asians have a lower obesity
prevalence when compared to other ethnic groups.
However, Asians born in the United States are four times
more likely to be obese
than their foreign-born counterparts.
Less educated people have a higher
prevalence of obesity than their
counterparts, with the exception of black women.
States in the Southeast have a
higher prevalence than those on the West Coast
or in the Midwest and Northeast.
16 percent of children and
adolescents are overweight, and 34 percent are at
risk of becoming overweight in 2003Ð2004.
White children and adolescents had
the lowest prevalence of being overweight
or at risk, compared with their black and Mexican
counterparts.
"Our analysis showed patterns of obesity or overweight
for various groups
of Americans. All groups consistently increased in obesity
or overweight
prevalence, but the increase varied by group, making this
public health issue
complex. More research needs to be completed to look into
the underlying
causes," said May A. Beydoun, co-author of the study and a
postdoctoral fellow
in the Bloomberg School's Department of International
Health. "Obesity is
likely to continue to increase, and if nothing is done, it
will soon become the
leading preventable cause of death in the United
States."
Wang and Beydoun co-authored the study, which was
supported by grants from
the Johns Hopkins Bloomberg School of Public Health, the
National Institute of
Diabetes and Digestive and Kidney Diseases/National
Institutes of Health and the
U.S. Department of Agriculture.
In a related study, the co-authors published a
research article in the May
7 issue of the European Journal of Clinical Nutrition that
found people purchase
foods based on their income level and perception of a
food's health benefit and
cost. Ethnicity, gender and environmental factors also
impact people's food
choices.