The dramatic increase in the incidence of obesity in the past 20 years has landed the U.S. in the midst of what truly can be characterized as an obesity epidemic.
The terms “overweight” and “obesity” are defined using the concept of body mass index. BMI measures body weight in relation to height, specifically weight in pounds divided by height in inches squared, multiplied by 703. In the U.S., people are considered overweight if their BMI is from 25 to 29.9, obese if their BMI is from 30 to 39.9, and morbidly obese if their BMI is 40 or more. Using this method, a five-foot-nine adult ideally should weigh between 126 and 169 pounds, and would be classified as obese at a weight greater than 203 pounds and as morbidly obese at 271 pounds or more. For children, the BMI numbers are plotted on a sex-specific BMI-for-age growth chart in order to obtain a percentile ranking, which allows for the fact that the amount of body fat changes with age and is different between girls and boys. A child whose weight is equal to or greater than the 95th percentile of BMI-for-age is considered overweight.
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| Data Source: Centers for Disease Control, ICD-9 BMI Formula for Adults: Weight (lb) ÷ (height [in]2 x 703; weight (kg) ÷ (height [m])2 |
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U.S. Epidemic
In 1990, 10 states had an incidence of obesity less than 10 percent and no
state had an incidence greater than 15 percent. Sixteen years later, only
four states had a prevalence of adult obesity which was less than 20 percent,
and in two states (Mississippi and West Virginia) more than 30 percent of
the adult population was obese. Currently 66 percent of the adult U.S. population
meets the definition of being either overweight or obese.
Unfortunately, this epidemic is affecting children and adolescents as well. In the decade of the 1970s, the incidence of obesity was 4 percent to 6 percent in children and adolescents ages 2 to 19. Current data suggests that 17 percent of 2- to 19-year-olds is now obese, including 14 percent of 2- to 5-year-olds.
There are also striking differences in obesity rates in the U.S. based on sex, ethnicity, and economic status. Approximately 53 percent of non-Hispanic black women and 51 percent of Mexican-American women age 40 to 59 are obese compared to 39 percent of non-Hispanic white women of the same age, according to the latest figures from the Centers for Disease Control and Prevention. Among women age 60 and older, 61 percent of non-Hispanic black women were obese compared with 37 percent of Mexican-American women and 32 percent of non-Hispanic white women. Adults age 40 to 59 had the highest obesity prevalence compared with all other age groups, with approximately 40 percent of men and 41 percent of women in this age group being considered obese.
Socioeconomic and environmental factors also influence obesity rates. Economically depressed areas may lack open spaces and sidewalks, resources that could encourage outdoor activities. Additionally, residents of these areas may feel that participation in outdoor activities is unsafe and thus are more likely to remain sedentary at home. Other data have suggested that grocery stores and supermarkets located in economically poorer areas of cities tend to offer fewer healthy choices. Cost often is prohibitive when food choices are made; high-calorie processed foods often cost less and are easier to prepare than healthier food such as fresh fruits and vegetables. However, the link between low socioeconomic status and obesity has not been established conclusively, and it should be noted that some recent research shows obesity increasing among high-income groups, as well.
“Globesity”
This problem is not be restricted to the U.S. alone. The World Health Organization
recently has begun employing the term “globesity” to represent the global
epidemic of overweight and obesity. In developing countries, underweight
and overweight individuals may often exist in the same setting, signifying
complex nutrition problems and affecting global policymaking. Obesity is
increasing in impoverished areas of countries around the world, especially
in urban areas of more developed regions. Obesity rates in poorer countries
have continued to rise while rates of underweight adults and children have
decreased. For example, in a region in northeast Brazil approximately 10
percent of children remain underweight while 25 percent of adults are now
overweight. In an area of northern India, 16 percent of people are thought
to be malnourished, but 28 percent are obese. Similar trends have been observed
in China and Russia. Nutrition researchers predict that this global epidemic
will continue as most of the world’s population growth is in urban areas
where there tends to be a more sedentary lifestyle and where food supplies
tend to be calorie dense and less balanced.
Economic Implications
Current economic models suggest that healthcare expenditures related to obesity
now exceed $100 billion annually in the U.S. Approximately half of these
costs are paid by Medicaid and Medicare. Pooled data analyses have suggested
that obese adults age 65 and younger have annual medical expenditures that
are 36 percent higher than for those of normal weight. Annual medical spending
attributable to obesity now rivals that attributable to cigarette smoking.
This fact has prompted discussion of whether government and private insurers
should be more involved in covering obesity prevention and treatment programs
much as they have done for cigarette smoking. Recent data also have shown
that healthcare spending on obese people accounted for 27 percent of the
growth and inflation-adjusted-per-capita healthcare spending between 1987
and 2001. Assuming that the overweight and obese population in the U.S. continues
to increase, this trend will have obvious implications for growth in healthcare
spending.
Allen K. Sills, MD, is in practice at Semmes-Murphey Neurologic and Spine Institute, and he is associate professor of neurosurgery at the University of Tennessee Medical School in Memphis. The author reported no conflicts for disclosure.
For Further Information
- The Economics of Obesity, www.ers.usda.gov/Publications/EFAN04004/
- National Center for Health Statistics at the Centers for Disease Control and Prevention, www.cdc.gov/nchs
- Trends: Impact of obesity on rising medical spending; National medical spending attributable to overweight and obesity–how much and who’s paying?www.healthaffairs.org
- The United Nations System Standing Committee on Nutrition, www.unsystem.org/SCN
- Understanding Adult Obesity, https://win.niddk.nih.gov/publications/understanding.htm
- World Health Organization Global Database on Body Mass Index, https://www.who.int/bmi/index.jsp