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.
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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.
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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
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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. |
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