Customize your JAMA Network experience by selecting one or more topics from the list below.
Hedley AA, Ogden CL, Johnson CL, Carroll MD, Curtin LR, Flegal KM. Prevalence of Overweight and Obesity Among US Children, Adolescents, and Adults, 1999-2002. JAMA. 2004;291(23):2847–2850. doi:10.1001/jama.291.23.2847
Context The prevalence of overweight and obesity has increased markedly in the
last 2 decades in the United States.
Objective To update the US prevalence estimates of overweight in children and
obesity in adults, using the most recent national data of height and weight
Design, Setting, and Participants As part of the National Health and Nutrition Examination Survey (NHANES),
a complex multistage probability sample of the US noninstitutionalized civilian
population, both height and weight measurements were obtained from 4115 adults
and 4018 children in 1999-2000 and from 4390 adults and 4258 children in 2001-2002.
Main Outcome Measure Prevalence of overweight (body mass index [BMI] ≥95th percentile
of the sex-specific BMI-for-age growth chart) among children and prevalence
of overweight (BMI, 25.0-29.9), obesity (BMI ≥30.0), and extreme obesity
(BMI ≥40.0) among adults by sex, age, and racial/ethnic group.
Results Between 1999-2000 and 2001-2002, there were no significant changes among
adults in the prevalence of overweight or obesity (64.5% vs 65.7%), obesity
(30.5% vs 30.6%), or extreme obesity (4.7% vs 5.1%), or among children aged
6 through 19 years in the prevalence of at risk for overweight or overweight
(29.9% vs 31.5%) or overweight (15.0% vs 16.5%). Overall, among adults aged
at least 20 years in 1999-2002, 65.1% were overweight or obese, 30.4% were
obese, and 4.9% were extremely obese. Among children aged 6 through 19 years
in 1999-2002, 31.0% were at risk for overweight or overweight and 16.0% were
overweight. The NHANES results indicate continuing disparities by sex and
between racial/ethnic groups in the prevalence of overweight and obesity.
Conclusions There is no indication that the prevalence of obesity among adults and
overweight among children is decreasing. The high levels of overweight among
children and obesity among adults remain a major public health concern.
The prevalence of overweight and obesity is considered an important
public health issue in the United States.1,2 Healthy
People 2010 identified overweight and obesity as 1 of the 10 leading health
indicators.1 The data source for monitoring
the national prevalence of overweight and obesity is the National Health and
Nutrition Examination Survey (NHANES).1 Since
1960, NHANES data on measured height and weight have been used to determine
obesity levels in the United States.3 Estimates
of the prevalence of overweight and obesity among the US population in 1999-2000
showed continuing increases among both children and adults.3,4 This
report is intended to update those estimates with additional NHANES data from
In NHANES, a representative sample of the US noninstitutionalized civilian
population was selected using a complex multistage probability design. Height
and weight measurements were obtained using standardized techniques and equipment.
Adults were defined as persons aged 20 years or older and children as persons
aged 2 through 19 years. For adults, overweight, obesity, and extreme obesity were
defined as a body mass index (BMI, calculated as weight in kilograms divided
by the square of height in meters) of 25.0 to 29.9, 30.0 or more, and 40.0
or more, respectively.3,5
For children, the 2000 Centers for Disease Control and Prevention Growth
Charts for the United States were used to define overweight and at risk for
overweight.4,6 The sex-specific
BMI-for-age growth charts are based on national data from 1963 to 1994.6At risk for overweight was
defined as at or above the 85th percentile but less than the 95th percentile
of the sex-specific BMI for age, as defined by the growth chart. The category
at risk for overweight is intended to identify children who should be referred
for a second level of screening to determine if there are any additional health
risks that would warrant intervention.7Overweight was defined as at or above the 95th percentile
of the sex-specific BMI-for-age growth chart.
Data were analyzed using the statistical programs SAS version 8.02 (SAS
Institute Inc, Cary, NC) and SUDAAN version 8.0 (Research Triangle Institute,
Research Triangle Park, NC). Pregnant females were excluded from the analyses.
All analyses used sample weights to account for differential probabilities
of selection into the sample, nonresponse, and noncoverage. Data for adults
were age-standardized to the 2000 US Census using age groups 20 through 39
years, 40 through 59 years, and 60 years or older. Standard errors were estimated
using Taylor series linearization. The t statistic
was used to test hypotheses at the overall significance level of P<.05. The Bonferroni method was used to adjust for multiple comparisons
across 3 racial/ethnic groups.
Sample sizes and selected demographic characteristics are shown in Table 1. Between 1999-2000 and 2001-2002,
there were no significant changes in the overall prevalence of overweight
and obesity among adults or at risk for overweight and overweight among children.
In 2001-2002, 65.7% of adults (SE, 0.6) were either overweight or obese, 30.6%
(1.1) were obese, and 5.1% (0.5) were extremely obese compared with 64.5%
(1.6), 30.5% (1.5), and 4.7% (0.6), respectively, in 1999-2000.3 Among
children aged 6 through 19 years in 2001-2002, 31.5% (1.3) were at risk for
overweight or overweight and 16.5% (1.0) were overweight compared with 29.9%
(1.7) and 15.0% (1.0), respectively, in 1999-2000.
Because 4 years of data yield more precise estimates than 2 years, the
remainder of this report presents estimates based on the NHANES 1999-2002
data. The prevalence of at risk for overweight and overweight for children
in 1999-2002 is shown in Table 2.
Nearly one third (31.0%) of children aged 6 through 19 years were either at
risk for overweight or overweight and 16.0% were considered overweight. For
girls aged 6 through 19 years, the prevalence of overweight among non-Hispanic
white girls was significantly lower than that of non-Hispanic black and Mexican
American girls. For boys aged 6 through 19 years, Mexican American boys had
a significantly higher prevalence of overweight than their non-Hispanic white
and black counterparts.
The percentage of adults at a healthy weight (BMI, 18.5-24.9) was 33.0%.
The prevalence of overweight, obesity, and extreme obesity among adults in
1999-2002 is shown in Table 3 and Table 4. Among adults aged at least 20
years, 65.1% were overweight or obese, 30.4% were obese, and 4.9% were extremely
obese. In almost every age and racial/ethnic group, the prevalence of overweight
or obesity exceeded 50%.
The prevalence of obesity by age, sex, and racial/ethnic group ranged
from 22.9% of non-Hispanic white men aged 20 through 39 years to 50.6% of
non-Hispanic black women aged 40 through 59 years. Among women, non-Hispanic
black women had the highest level of extreme obesity (13.5%) compared with
5.5% and 5.7% of non-Hispanic white and Mexican American women, respectively.
There was no significant difference in the prevalence of obesity among men
across racial/ethnic categories for all age groups. Among women aged at least
20 years, the prevalence of obesity differed significantly between racial/ethnic
groups, with non-Hispanic white women having the lowest prevalence (30.7%),
non-Hispanic black women having the highest (49.0%), and the prevalence among
Mexican American women falling in between (38.4%). The prevalence of obesity
was significantly higher among women than men (P<.01).
The data from NHANES 1999-2002 presented herein provide updated estimates
of the prevalence of overweight and obesity among children and adults in the
United States. Previous reports based on NHANES data have shown continuing
increases in overweight and obesity among adults and in overweight among children
and adolescents during the past 2 decades.3,4 This
increase has been attributed to environmental factors related to both calorie
intake and physical activity.8
Estimates from NHANES 1999-2000 provided evidence of a continuing increase
in the prevalence of obesity.3,4 The
current prevalence estimates based on 4 years of data further support the
1999-2000 findings. Four years of data yield more stable and precise estimates
of the prevalence of obesity because data were collected from a greater number
of locations and sample sizes were larger.
The overall prevalence of overweight and obesity showed no significant
changes between 1999-2000 and 2001-2002 for either children or adults. However,
due to the short time frame as well as sampling and nonsampling errors, it
is difficult to assess trends between 1999-2000 and 2001-2002. Although it
may be possible to make broad comparisons, caution is advised in comparing
the 1999-2000 data with the 2001-2002 data. This is especially true for demographic
subgroups in which the sample size is relatively small. Some apparently large
changes within racial/ethnic groups (eg, Mexican American adults) were not
statistically significant and may simply reflect the uncertainty of estimates
based on 2 years of NHANES data. There are some indications of a possible
increase among children and non-Hispanic white adults. Further monitoring
is warranted to determine whether the upward trend in the prevalence of obesity
is continuing or leveling off.
The prevalence estimates of obesity from NHANES 1999-2002 exceed the
most recent estimates of adult obesity from the Behavioral Risk Factor Surveillance
System (BRFSS) and the National Health Interview Survey (NHIS).9,10 In
2001, the prevalence of obesity among adults aged at least 18 years was 20.9%
based on the BRFSS and 22.5% based on the NHIS.9,10 In
NHANES 1999-2002, the prevalence of obesity was 30.4% among adults aged at
least 20 years. This discrepancy between estimates is expected because the
BRFSS and NHIS estimates are based on self-reported height and weight, which
yield lower estimates of the prevalence of overweight and obesity.11
The NHANES results indicate continuing disparities between racial/ethnic
groups in the prevalence of overweight and obesity. The prevalence of overweight
was significantly higher among Mexican American boys than among non-Hispanic
white and black boys. However, there were no significant differences in the
prevalence of obesity by racial/ethnic group for adult men. The prevalence
of overweight for girls starting at age 6 years and the prevalence of obesity
for women of all age groups were significantly higher for non-Hispanic blacks
vs non-Hispanic whites. Although Mexican American girls did not have significantly
lower prevalence levels of overweight than non-Hispanic black girls, the prevalence
of obesity among Mexican American women was significantly lower than among
non-Hispanic black women.
The most recent NHANES estimates indicate neither an increase nor decrease
in the prevalence of obesity among adults or overweight among children. In
1999-2002, the percentage of adults at a healthy weight (33.0%) was approximately
half of the Healthy People 2010 target level of 60%.1 The
prevalence of obesity among adults (30.4%) was double the target prevalence
(15%).1 Among children aged 6 through 19 years,
the prevalence of overweight (16.0%) was more than 3 times the target prevalence
(5%).1 Substantial progress will need to be
made in the efforts to lower the prevalence of overweight and obesity if the
goals of Healthy People 2010 are to be met.