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Mokdad AH, Ford ES, Bowman BA, et al. Prevalence of Obesity, Diabetes, and Obesity-Related Health Risk Factors,
2001. JAMA. 2003;289(1):76–79. doi:10.1001/jama.289.1.76
Context Obesity and diabetes are increasing in the United States.
Objective To estimate the prevalence of obesity and diabetes among US adults in
Design, Setting, and Participants Random-digit telephone survey of 195 005 adults aged 18 years or
older residing in all states participating in the Behavioral Risk Factor Surveillance
System in 2001.
Main Outcome Measures Body mass index, based on self-reported weight and height and self-reported
Results In 2001 the prevalence of obesity (BMI ≥30) was 20.9% vs 19.8% in
2000, an increase of 5.6%. The prevalence of diabetes increased to 7.9% vs
7.3% in 2000, an increase of 8.2%. The prevalence of BMI of 40 or higher in
2001 was 2.3%. Overweight and obesity were significantly associated with diabetes,
high blood pressure, high cholesterol, asthma, arthritis, and poor health
status. Compared with adults with normal weight, adults with a BMI of 40 or
higher had an odds ratio (OR) of 7.37 (95% confidence interval [CI], 6.39-8.50)
for diagnosed diabetes, 6.38 (95% CI, 5.67-7.17) for high blood pressure,
1.88 (95% CI,1.67-2.13) for high cholesterol levels, 2.72 (95% CI, 2.38-3.12)
for asthma, 4.41 (95% CI, 3.91-4.97) for arthritis, and 4.19 (95% CI, 3.68-4.76)
for fair or poor health.
Conclusions Increases in obesity and diabetes among US adults continue in both sexes,
all ages, all races, all educational levels, and all smoking levels. Obesity
is strongly associated with several major health risk factors.
Obesity and diabetes are major causes of morbidity and mortality in
the United States.1-3 Evidence
from several studies indicates that obesity and weight gain are associated
with an increased risk of diabetes4,5 and
that intentional weight loss reduces the risk that overweight people will
develop diabetes.6 Each year, an estimated
300 000 US adults die of causes related to obesity,7 and
diabetes is the sixth leading cause of death.3 Correspondingly,
both obesity and diabetes generate immense health care costs.8,9
We recently reported that the prevalence of obesity and diabetes among
US adults increased substantially from 1990 to 2000.10 We
used data from the 2001 Behavioral Risk Factor Surveillance System (BRFSS)
to examine whether these increases are continuing. In addition, we examined
the association between obesity and several other important health risk factors,
as well as self-rated general health.
The BRFSS is a cross-sectional telephone survey conducted by the Centers
for Disease Control and Prevention and state health departments. The BRFSS
questionnaire consists primarily of questions about personal behaviors that
increase risk for 1 or more of the 10 leading causes of death in the United
States. The BRFSS uses a multistage cluster design based on random-digit dialing
to select a representative sample from each state's noninstitutionalized civilian
residents aged 18 years or older. Data from each state are pooled to produce
nationally representative estimates. A detailed description of the survey
methods is available elsewhere.11,12
The 2001 BRFSS included questions on health status, health care access,
exercise, hypertension awareness, cholesterol awareness, asthma, diabetes,
arthritis, immunization, tobacco use, alcohol consumption, firearms, disability,
physical activity, prostate cancer screening, colorectal cancer screening,
and human immunodeficiency virus or acquired immunodeficiency syndrome (all
BRFSS questionnaires from 1991 to 2002 are available at http://www.cdc.gov/brfss).
We used data on self-reported weight and height to calculate body mass
index (BMI), calculated as weight in kilograms divided by the square of height
in meters. Participants were classified as overweight (class 1) if their BMI
ranged from 25 through 29.9. We further divided obesity (BMI ≥30) into
2 levels to analyze the association between BMI groups and medical conditions:
BMI of 30 through 39.9, class 2; BMI of 40 or higher, class 3.13 Self-reported
weight and height were assessed by asking, "About how much do you weigh without
shoes?" and "About how tall are you without shoes?" Diagnosed diabetes was
assessed by asking, "Have you ever been told by a doctor that you have diabetes?"
The answer was coded yes or no to be similar to our previous reports. Those
with gestational diabetes were considered to have diabetes. The type of diabetes
was not assessed.
High blood pressure was assessed by asking, "Have you ever been told
by a doctor, nurse, or other health professional that you have high blood
pressure?" High cholesterol was assessed by asking, "Have you ever been told
by a doctor, nurse, or other health professional that your blood cholesterol
is high?" Asthma was assessed by asking, "Have you ever been told by a doctor,
nurse, or other health professional that you had asthma?" Arthritis was assessed
by asking, "Have you ever been told by a doctor that you have arthritis?"
Health status was assessed by asking, "Would you say that in general your
health is: excellent, very good, good, fair, or poor?"
SAS and SUDAAN statistical software programs were used in the analyses
and to account for the complex sampling design.14,15 We
used Proc Logistic in SUDAAN to generate the odds ratios (ORs) and their 95%
confidence intervals (CIs) for the association of BMI and medical conditions.
Because of the large sample size (195 005 participants), we have not
emphasized statistical testing.
The prevalence of obesity among US adults (Table 1) increased to 20.9% in 2001 from 19.8% in 2000, an increase
of 5.6%. Since 1991 the percentage of those who were obese increased by 74%
(1991 prevalence, 12%). That prevalence rate represents an estimated 21.4
million obese men and 22.9 million obese women, for a total of 44.3 million
obese US adults. The percentage of adults with a BMI of 40 or higher was 2.3%
(1.7% men, 2.8% women) vs 2.1% in 2000 and 0.9% in 1991. Among racial groups,
blacks had the highest rate of obesity (31.1%). Among states, Mississippi
had the highest rate of obesity (25.9%) and Colorado the lowest (14.4%; Table 2, Figure 1, A). Since 1991, the percentage of overweight
adult participants increased from 45% to 58%. Of those overweight in 2001,
65.9% were men and 49.9% were women.
The prevalence of those diagnosed with diabetes increased to 7.9% in
2001 from 7.3% in 2000, an increase of 8.2% and an increase of 61% since 1990
(1990 prevalence, 4.9%). Thus, in 2001, an estimated 16.7 million US adults
could have been diagnosed as having diabetes (6.9 million men; 9.8 million
women). In 2001, 3.4% of US adults (2.9% men, 3.8% women) were both obese
and had diabetes, an increase of 1.4% in 1991. Blacks had the highest rate
of diagnosed diabetes (11.2%) among all race groups, and adults with less
than a high school education had the highest rate (13.0%) among the educational
levels. Of US adults aged 60 years or older, 15.1% had diagnosed diabetes.
Alabama had the highest rate of diagnosed diabetes (10.5%) and Minnesota the
lowest (5.0%; Table 2, Figure 1, B).
Both overweight and obesity were significantly associated with diabetes,
high blood pressure, high cholesterol levels, asthma, arthritis, and fair
or poor health status (Table 3).
Compared with adults with normal weight, those with a BMI of 40 or higher
had an OR of 7.37 (95% CI, 6.39-8.50) for diagnosed diabetes, 6.38 (95% CI,
5.67-7.17) for high blood pressure, 1.88 (95% CI, 1.67-2.13) for high cholesterol
levels, 2.72 (95% CI, 2.38-3.12) for asthma, 4.41 (95% CI, 3.91-4.97) for
arthritis, and 4.19 (95% CI, 3.68-4.76) for fair or poor health.
Our study, the largest telephone survey of adults in the United States,
shows a continuing increase of obesity and diabetes in both sexes, all ages,
all races, all educational levels, and all smoking levels. Because of the
strong association between overweight and obesity and several well-established
risk factors for morbidity and mortality, reversing the obesity epidemic is
an urgent priority.
However, these rates are no doubt substantial underestimates. First,
individuals without telephones are not included in BRFSS, and such persons
are likely to be of low socioeconomic status, a factor associated with both
obesity and diabetes.16,17 Second,
in validation studies of self-reported weight and height, overweight participants
tend to underestimate their weight, and all participants tend to overestimate
their height.18-20 Recent
estimates of obesity among US adults is about 30% based on measured weight
and height.21 Third, undiagnosed diabetes was
not counted; recent estimates indicate that about 35% of all persons with
diabetes have not been diagnosed.3
Both obesity and type 2 diabetes are preventable. Previous studies have
demonstrated that changes in lifestyle are effective in preventing both diabetes
and obesity in high-risk adults with impaired glucose tolerance.22,23 Increasing
physical activity, improving diet, then sustaining these lifestyle changes
can reduce both body weight and risk of diabetes. We found that in 2001, 25.5%
of US adults did not engage in any leisure-time physical activity. This is
a modest decrease from a 27.0% rate in 2000, but it shows that current physical
activity levels are still far below what they need to be.
We previously reported that less than 20% of US adults who were trying
to lose or maintain weight were following recommendations to eat fewer calories
and increase physical activity to at least 150 minutes per week.10 Health
professionals must continue to stress the importance of a balanced diet and
physical activity for healthy weight loss. In US society, men and women must
overcome many obstacles to make the best choices for optimal health.
Although clinical preventive services to identify and control hypertension,
elevated cholesterol levels, asthma, arthritis, and diabetes remain important
medical priorities nationally, development and implementation of national
programs to promote a balanced diet, increase physical activity, and maintain
weight control must be national priorities as well.