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Facts and Statistics

What is obesity? Who is obese? How does obesity develop over time? How can it affect individuals and our society? What can be done about it? How does obesity look when illustrated with statistics? We will address these questions in this section of the Obesity Network.

 

Statistics Related to Overweight and Obesity

 

Nearly two-thirds of adults in the United States are overweight, and 30.5 percent are obese, according to data from the 1999-2000 National Health and Nutrition Examination Survey (NHANES). This fact sheet presents statistics on the prevalence of overweight and obesity in the U.S., as well as their disease, mortality, and economic costs. To understand these statistics, it is necessary to know how overweight and obesity are defined and measured. This fact sheet also explains why statistics from different sources may not match.

Overweight and obesity are known risk factors for:

  • diabetes
  • heart disease
  • stroke
  • hypertension
  • gallbladder disease
  • osteoarthritis (degeneration of cartilage and bone of joints)
  • sleep apnea and other breathing problems
  • some forms of cancer (uterine, breast, colorectal, kidney, and gallbladder)

Obesity is also associated with:

  • high blood cholesterol
  • complications of pregnancy
  • menstrual irregularities
  • hirsutism (presence of excess body and facial hair)
  • stress incontinence (urine leakage caused by weak pelvic-floor muscles)
  • psychological disorders such as depression
  • increased surgical risk

 

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What are overweight and obesity?

Overweight refers to an excess of body weight compared to set standards. The excess weight may come from muscle, bone, fat, and/or body water. Obesity refers specifically to having an abnormally high proportion of body fat.[1] A person can be overweight without being obese, as in the example of a bodybuilder or other athlete who has a lot of muscle. However, many people who are overweight are also obese.

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How are overweight and obesity measured?

A number of methods are used to determine if someone is overweight or obese. Some are based on the relation between height and weight; others are based on measurements of body fat. The most commonly used method today is body mass index (BMI).

BMI can be used to screen for both overweight and obesity in adults. It is the measurement of choice for many obesity researchers and other health professionals, as well as the definition used in most published information on overweight and obesity. BMI is a calculation based on height and weight, and it is not gender-specific. BMI does not directly measure percent of body fat, but it is a more accurate indicator of overweight and obesity than relying on weight alone.

BMI is found by dividing a person’s weight in kilograms by height in meters squared. The mathematical formula is:
weight (kg) / height squared (m²).

To determine BMI using pounds and inches, multiply your weight in pounds by 704.5,* then divide the result by your height in inches, and divide that result by your height in inches a second time. (Or you can use the BMI calculator at http://www.nhlbisupport.com/bmi/, or check the chart shown below that has calculated BMI for you.)

* The multiplier 704.5 is used by the National Institutes of Health. Other organizations may use a slightly different multiplier; for example, the American Dietetic Association suggests multiplying by 700. The variation in outcome (a few tenths) is insignificant.

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Body Mass Index Table (pop up)

 

An expert panel convened by the National Heart, Lung, and Blood Institute (NHLBI) in cooperation with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), both part of the National Institutes of Health (NIH) identified overweight as a BMI of 25-29.9 kg/m², and obesity as a BMI of 30 kg/m² or greater. However, overweight and obesity are not mutually exclusive, since people who are obese are also overweight.[1] Defining overweight as a BMI of 25 or greater is consistent with the recommendations of the World Health Organization [2] and most other countries.

Calculating BMI is simple, quick, and inexpensive--but it does have limitations. One problem with using BMI as a measurement tool is that very muscular people may fall into the "overweight" category when they are actually healthy and fit. Another problem with using BMI is that people who have lost muscle mass, such as the elderly, may be in the "healthy weight" category--according to their BMI--when they actually have reduced nutritional reserves. BMI, therefore, is useful as a general guideline to monitor trends in the population, but by itself is not diagnostic of an individual patient’s health status. Further evaluation of a patient should be performed to determine his or her weight status and associated health risks.

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Why do statistics about overweight and obesity differ?

The definitions or measurement characteristics for overweight and obesity have varied over time, from study to study, and from one part of the world to another. The varied definitions affect prevalence statistics and make it difficult to compare data from different studies. Prevalence refers to the total number of existing cases of a disease or condition in a given population at a given time. Some overweight- and obesity-related prevalence rates are presented as crude or unadjusted estimates, while others are age-adjusted estimates. Unadjusted prevalence estimates are used to present cross-sectional data for population groups at a given point or time period. For age-adjusted rates, statistical procedures are used to remove the effect of age differences in populations that are being compared over different time periods. Unadjusted estimates and age-adjusted estimates will yield slightly different values.

Previous studies in the United States have used the 1959 or the 1983 Metropolitan Life Insurance tables of desirable weight-for-height as the reference for overweight.[3] More recently, many Government agencies and scientific health organizations have estimated overweight using data from a series of cross-sectional surveys called the National Health Examination Surveys (NHES) and the National Health and Nutrition Examination Surveys (NHANES). The National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC) conducted these surveys. Each had three cycles: NHES I, II, and III spanned the period from 1960 to 1970, and NHANES I, II, and III were conducted in the 1970’s, 1980’s, and early 1990’s. Since 1999, NHANES has become a continuous survey.

Many reports in the literature use a statistically derived definition of overweight from NHANES II (1976-1980). This definition (based on the gender-specific 85th percentile values of BMI for 20 to 29 year olds) is a BMI greater than or equal to (>) 27.3 for women and 27.8 for men. NHANES II further defines "severe overweight" (based on 95th percentile values) as BMI > 31.1 for men and BMI > 32.2 for women.[4] Some studies round these numbers to a whole number, which affects the statistical prevalence. In 1995, the World Health Organization recommended a classification for three "grades" of overweight using BMI cutoff points of 25, 30, and 40.[5] The International Obesity Task Force suggested an additional cutoff point of 35 and slightly different terminology.[6]

The expert panel convened by NHLBI and NIDDK released a report in June 1998, that provided definitions for overweight and obesity similar to those used by the World Health Organization. The panel identified overweight as a BMI > 25 to less than (<)30, and obesity as a BMI > 30. These definitions, widely used by the Federal government and increasingly by the broader medical and scientific communities, are based on evidence that health risks increase more steeply in individuals with a BMI > 25.

BMI cutoff points are a guide for definitions of overweight and obesity and are useful for comparative purposes across populations and over time; however, the health risks associated with overweight and obesity are on a continuum and do not necessarily correspond to rigid cutoff points. For example, an overweight individual with a BMI of 29 does not acquire additional health consequences associated with obesity simply by crossing the BMI threshold > 30. However, health risks generally increase with increasing BMI.

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Prevalence statistics related to overweight and obesity*

 

* The statistics presented here are based on the following definitions unless otherwise specified: overweight = BMI> 25 to < 30; obesity = BMI > 30.

 

Overweight and obesity are found worldwide, and the prevalence of these conditions in the United States ranks high along with other developed nations. Approximately 300,000 adult deaths in the United States each year are attributable to unhealthy dietary habits and physical inactivity or sedentary behavior. [7]

Below are some frequently asked questions and answers about overweight and obesity statistics. Data are based on NHANES 1999-2000. Unless otherwise specified, the figures given represent age-adjusted estimates. Population numbers are based on the U.S. Census Bureau Census 2000.

Q: How many adults are overweight?

A: Nearly two-thirds of U.S. adults are overweight (BMI > 25, which includes those who are obese).[8]

All adults (20+ years old): 129.6 million (64.5 percent)
Women (20+ years old): 64.5 million (61.9 percent)
Men (20+ years old): 65.1 million (67.2 percent)

 

Q: How many adults are obese?

A: Nearly one-third of U.S. adults are obese (BMI > 30).[8]

All adults (20+ years old): 61.3 million (30.5 percent)
Women (20+ years old): 34.7 million (33.4 percent)
Men (20+ years old): 26.6 million (27.5 percent)

 

Q: How many adults are at a healthy weight?

A: Less than half of U.S. adults have a healthy weight (BMI > 18.5 to < 25).[9]

All adults (20-74 years old): 67.3 million (33.5 percent)
Women (20-74 years old): 36.7 million (35.3 percent)
Men (20-74 years old): 30.6 million (31.8 percent)

 

Q: How has the prevalence of overweight and obesity in adults changed over the years?

A: The prevalence has steadily increased over the years among both genders, all ages, all racial/ethnic groups, all educational levels, and all smoking levels.10 From 1960 to 2000, the prevalence of overweight (BMI > 25 to < 30) increased from 31.5 to 33.6 percent in U.S. adults aged 20 to 74.[9] The prevalence of obesity (BMI > 30) during this same time period more than doubled from 13.3 to 30.9 percent, with most of this rise occurring in the past 20 years.8 From 1988 to 2000, the prevalence of extreme obesity (BMI > 40) increased from 2.9 to 4.7 percent, up from 0.8 percent in 1960.3,8 In 1991, four states had obesity rates of 15 percent or higher, and none had obesity rates above 16 percent. By 2000, every state except Colorado had obesity rates of 15 percent or more, and 22 states had obesity rates of 20 percent or more.11 The prevalence of overweight and obesity generally increases with advancing age, then starts to decline among people over 60.[3]

 

Q: What is the prevalence of overweight and obesity in minorities?

A: The age-adjusted prevalence of combined overweight and obesity (BMI > 25) in racial/ethnic minorities--especially minority women--is generally higher than in whites in the United States.[8]

Non-Hispanic Black women: 77.3%
Mexican American women: 71.9%
Non-Hispanic White women: 57.3%
Non-Hispanic Black men: 60.7%
Mexican American men: 74.7%
Non-Hispanic White men: 67.4%

(Statistics are for populations 20+ years old)

Studies using this definition of overweight and obesity provide ethnicity-specific data only for these three racial-ethnic groups. Studies using definitions of overweight and obesity from NHANES II have reported a high prevalence of overweight and obesity among Hispanics and American Indians. The prevalence of overweight (BMI > 25) and obesity (BMI > 30) in Asian Americans is lower than in the population as a whole.[1]


 

Figure 1. Age-adjusted prevalence of overweight (BMI 25-29.9) and obesity (BMI > 30)

Source: CDC/NCHS, Health, United States, 2000

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* Overweight is defined by the sex- and age-specific 95th percentile cutoff points of the revised NCHS/CDC growth charts. The revised growth charts incorporate smoothed BMI percentiles and are based on data from NHES II (1963-65) and III (1966-1970), and NHANES I (1971-1974), II (1976-1980), and III (1988-1994); the CDC BMI growth charts specifically excluded NHANES III data for children ages > 6 years.[13]


Q: What is the prevalence of overweight and obesity in children and adolescents?

A: While there is no generally accepted definition for obesity as distinct from overweight in children and adolescents, the prevalence of overweight* is increasing for children and adolescents in the United States. Approximately 15.3 percent of children (ages 6-11) and 15.5 percent of adolescents (ages 12-19) were overweight in 2000. An additional 15 percent of children and 14.9 percent of adolescents were at risk for overweight (BMI for age between the 85th and 95th percentile).[12]

 

Q: What is the prevalence of diabetes in people who are overweight or obese?

A: Among people diagnosed with type 2 (noninsulin-dependent) diabetes, 67 percent have a BMI > 27 and 46 percent have a BMI > 30.[14] About 17 million people in the U.S. have type 2 diabetes, accounting for more than 90 percent of diabetes cases.[15] An additional 20 million have impaired glucose tolerance, sometimes called pre-diabetes, which is a strong risk factor for developing diabetes later in life. An estimated 70 percent of diabetes risk in the U.S. can be attributed to excess weight.[16] For more statistics on diabetes, go to: www.diabetes.niddk.nih.gov/dm/pubs/statistics/index.htm.

 

Q: What is the prevalence of hypertension (high blood pressure) in people who are overweight or obese?

A: The age-adjusted prevalence of hypertension in overweight U.S. adults is 22.1 percent for men with BMI > 25 and < 27; 27.0 percent for men with BMI > 27 and < 30; 27.7 percent for women with BMI > 25 and < 27; and 32.7 percent for women BMI > 27 and < 30. In comparison, the prevalence of hypertension in adults who are not overweight (BMI <25) is 14.9 percent for men and 15.2 percent for women. The prevalence in adults who are obese (BMI > 30) is 41.9 percent for men and 37.8 percent for women.17 (Hypertension is defined as mean systolic blood pressure > 140 mm Hg, mean diastolic > 90 mm Hg, or currently taking antihypertensive medication.)

 

Q: What is the prevalence of high blood cholesterol in people who are overweight or obese?

A: The age-adjusted prevalence of high blood cholesterol (> 240 mg/dL) in overweight U.S. adults is 19.1 percent for men with BMI > 25 and < 27; 21.6 percent for men with BMI > 27 and < 30; 30.5 percent for women with BMI > 25 and < 27; and 29.6 percent for women BMI > 27 and < 30. In comparison, the prevalence of high cholesterol in adults who are not overweight (BMI <25) is 13.0 percent for men and 13.4 percent for women. The prevalence for adults who are obese (BMI > 30) is 22.0 percent for men and 27.0 percent for women.[17]

 

Q: What is the prevalence of cancer in people who are overweight or obese?

A: While direct prevalence information is not available, a recent study found that people whose BMI was 40 or more had death rates from cancer that were 52 percent higher for men and 62 percent higher for women than rates for normal-weight men and women. Overweight and obesity could account for 14 percent of cancer deaths among men and 20 percent among women in the U.S. In both men and women, higher BMI is associated with higher death rates from cancers of the esophagus, colon and rectum, liver, gallbladder, pancreas, and kidney. The same trend applies to cancers of the stomach and prostate in men and cancers of the breast, uterus, cervix, and ovaries in women.[18] Almost half of post-menopausal women diagnosed with breast cancer have a BMI > 29.19 In one study (the Nurses' Health Study), women gaining more than 20 pounds from age 18 to midlife doubled their risk of breast cancer, compared to women whose weight remained stable.[20]

 

Q: What is the mortality rate associated with obesity?

A: Most studies show an increase in mortality rate associated with obesity (BMI > 30). Obese individuals have a 50 to 100 percent increased risk of death from all causes, compared with normal-weight individuals (BMI 20-25). Most of the increased risk is due to cardiovascular causes.[21] Life expectancy of a moderately obese person could be shortened by 2 to 5 years. White men between 20 and 30 years old with a BMI > 45 could shorten their life expectancy by 13 years; white women in the same category could lose up to 8 years of life. Young African American men with a BMI > 45 could lose up to 20 years of life; African American women, up to 5.[22]

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Economic costs related to overweight and obesity

As the prevalence of overweight and obesity has increased in the United States, so have related health care costs--both direct and indirect. Direct health care costs refer to preventive, diagnostic, and treatment services (for example, physician visits, medications, and hospital and nursing home care). Indirect costs are the value of wages lost by people unable to work because of illness or disability, as well as the value of future earnings lost by premature death.

Most of the statistics presented below represent the economic cost of overweight and obesity in the United States in 1995, updated to 2001 dollars.[23] Unless otherwise noted, the statistics given are adapted from Wolf and Colditz,24 who based their data on existing epidemiological studies that defined overweight and obesity as a BMI > 29. Because the prevalence of overweight and obesity has increased since 1995, the costs today are higher than the figures given here.

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* A recent study estimated annual medical spending due to overweight and obesity (BMI > 25) to be as much as $92.6 billion in 2002 dollars (9.1 percent of U.S. health expenditures).[25]

Q: What is the cost of overweight and obesity?

A: Total cost: $117 billion , Direct cost: $61 billion,* Indirect cost: $56 billion (comparable to the economic costs of cigarette smoking)

 

Q: What is the cost of heart disease related to overweight and obesity?

A: Direct cost: $8.8 billion (17 percent of the total direct cost of heart disease, independent of stroke)

 

Q: What is the cost of type 2 diabetes related to overweight and obesity?

A: Total cost: $98 billion (in 2001)[16]

 

Q: What is the cost of osteoarthritis related to overweight and obesity?

A: Total cost: $21.2 billion, Direct cost: $5.3 billion, Indirect cost: $15.9 billion

 

Q: What is the cost of hypertension (high blood pressure) related to overweight and obesity?

A: Direct cost: $4.1 billion (17 percent of the total cost of hypertension)

 

Q: What is the cost of gallbladder disease related to overweight and obesity?

A: Total cost: $3.4 billion, Direct cost: $3.2 billion, Indirect cost: $187 million

 

Q: What is the cost of cancer related to overweight and obesity?

A: Breast cancer: Total cost: $2.9 billion, Direct cost: $1.1 billion, Indirect cost: $1.8 billion

Endometrial cancer: Total cost: $933 million, Direct cost: $310 million, Indirect cost: $623 million

Colon cancer: Total cost: $3.5 billion, Direct cost: $1.3 billion, Indirect cost: $2.2 billion

 

Q: What is the cost of lost productivity related to obesity?

A: The cost of lost productivity related to obesity (BMI > 30) among Americans ages 17-64 is $3.9 billion. This value considers the following annual numbers (for 1994):

Workdays lost related to obesity: 39.3 million
Physician office visits related to obesity: 62.7 million
Restricted activity days related to obesity: 239.0 million
Bed-days related to obesity: 89.5 million

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Other statistics related to overweight and obesity

Q: How much do we spend on weight-loss products and services?

A: Americans spend $33 billion annually on weight-loss products and services.[26] (This figure represents consumer dollars spent in the early 1990’s on all efforts at weight loss or weight maintenance including low-calorie foods, artificially sweetened products such as diet sodas, and memberships to commercial weight-loss centers.)

 

Q: How physically active is the U.S. population?

A: Less than one-third (31.8 percent) of U.S. adults get regular leisure-time physical activity (defined as light or moderate activity five times or more per week for 30 minutes or more each time and/or vigorous activity three times or more per week for 20 minutes or more each time). About 10 percent of adults do no physical activity at all in their leisure time.[27]

About 25 percent of young people (ages 12-21 years) participate in light to moderate activity (e.g., walking, bicycling) nearly every day. About 50 percent regularly engage in vigorous physical activity. Approximately 25 percent report no vigorous physical activity, and 14 percent report no recent vigorous or light to moderate physical activity.[28]

 

Q: What is the cost of lack of physical activity?

A: The direct cost of physical inactivity may be as high as $24.3 billion.[29]

 

Q: What are the benefits of physical activity?

A: In addition to helping to control weight, physical activity decreases the risk of dying from coronary heart disease and reduces the risk of developing diabetes, hypertension, and colon cancer.[28]

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References (see link)

 

 

Weight-control Information Network

1 WIN WAY
BETHESDA, MD 20892-3665
Phone: (202) 828-1025
FAX: (202) 828-1028
Toll-free number: 1-877-946-4627

Internet: www.niddk.nih.gov/health/nutrit/nutrit.htm
E-mail: win@info.niddk.nih.gov

The Weight-control Information Network (WIN) is a national service of the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, which is the Federal Government’s lead agency responsible for biomedical research on nutrition and obesity. Authorized by Congress (Public Law 103-43), WIN provides the general public, health professionals, the media, and Congress with up-to-date, science-based health information on weight control, obesity, physical activity, and related nutritional issues.

WIN answers inquiries, develops and distributes publications, and works closely


with professional and patient organizations and Government agencies to coordinate resources about weight control and related issues.

Publications produced by WIN are reviewed by both NIDDK scientists and outside experts.

This e-text is not copyrighted. WIN encourages users of this e-pub to duplicate and distribute as many copies as desired.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
National Institutes of Health

NIH Publication No. 03-4158
http://win.niddk.nih.gov/statistics/index.htm
July 2003

e-text posted: July 2003

 

 

Additional Resources:

See Also: Defining Overweight and Obesity

 

 

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