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The Epidemic of Overweight and Obesity
As a result of lifestyle and dietary changes, overweight and obesity
have reached epidemic proportions in the United States. The Body Mass Index
(BMI) is the most commonly used measure to define overweight and obesity. BMI
is a measure of weight in relation to height. BMI is calculated as weight in
pounds divided by the square of the height in inches, multiplied by 703.
According to the National Institutes of Health Clinical Guidelines,
overweight in adults is defined as a BMI between 25 lbs/in to 29.9
lbs/in; and obesity in adults is identified by a BMI of 30
lbs/in or greater. These definitions are based on
evidence that suggests that health risks are greater at or above a BMI of 25
lbs/in compared to those at a BMI below that level. The risk of
premature death increases with an increasing BMI. This increase in mortality
tends to be modest until a BMI of 30 lbs/in is reached.
P>Overweight and obesity are increasing in both genders and among all
population groups. In 1999, an estimated 61 percent of adults in the U.S. were
overweight or obese; this contrasts with the late 1970s, when an estimated 47
percent of adults were overweight or obese. Figure 9 demonstrates
the increasing prevalence of obesity among adults throughout the United States.
Figure 9 |
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Among women, the prevalence of overweight and obesity generally is
higher in women who are members of racial and ethnic minority populations than
in non-Hispanic white women. Among men, Mexican Americans have a
higher prevalence of overweight and obesity than non-Hispanic whites or
non-Hispanic blacks. For non-Hispanic men, the prevalence of overweight and
obesity among whites is slightly greater than among blacks.
Figure 10: Age-adjusted prevalence of overweight or
obesity
in selected groups, 1988-1994 |
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SOURCE: Surgeon General’s Call to Action to
Prevent and Decrease Overweight and Obesity, 2001 |
Disparities in prevalence of overweight and obesity also exist based on
socioeconomic status. For all racial and ethnic groups combined,
women of lower socioeconomic status (income <130 percent of the
poverty threshold) are approximately 50 percent more likely to be obese than
those with higher socioeconomic status (income > 130 percent of the poverty
threshold). Men are about equally likely to be obese whether they are in a low
or high socioeconomic group.
The overweight and obesity epidemic is not limited to adults. What is
particularly alarming is that the percentage of young people who are overweight
has almost doubled in the last 20 years for children aged 6-11 and almost
tripled for adolescents aged 12-19. In children and adolescents, overweight has
been defined as a sex- and age- specific BMI at or above the 95
percentile for a reference population, based on Centers for Disease Control and
Prevention (CDC) growth charts
Figure 11: Prevalence of Overweight in
Children
and Adolescents ages 6-19 |
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NOTES: Excludes pregnant women starting with
1971-74. Pregnancy status not available for 1963-65 and 1966-70. Data for
1963-65 are for children 6-11 years of age; data for 1966-70 are for
adolescents 12-17 years of age, not 12-19 years.
SOURCE: CDC/NCHS, NHES and
NHANES. |
Associated Health Risks of Not Maintaining a Healthy Weight
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