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Chapter 2

The Burden on Society

Increasing Prevalence

Obesity rates are climbing, not just in the U.S. but also in more and more countries around the world. Figure 1 shows the prevalence of obesity around the world (WHO 2000, WHO 2010a). The current number of obese Americans is the highest ever recorded. The escalating health risks due to obesity increase the prevalence of chronic disease and health care costs around the world.

Figure 1—Global weight increases, 1991 and most recent available

Obesity is defined as abnormal and excessive fat accumulation that may impair health (WHO 2009). To assess the health risks of obesity, clinicians use body mass index (BMI), a measure of weight compared with height. BMI is an imperfect tool, but provides a more useful measure of total body fat than weight alone. BMI risk levels are based on the association between BMI and morbidity/mortality for adults over 20 years of age and are the same for both sexes. According to BMI categories, all people with a BMI of 25 kg/m2 or greater are considered overweight. Overweight subcategories are pre-obese for a BMI of 25–29.9 kg/m2 and clinically obese for a BMI ≥30 kg/m2 (CDC 2010). As a general estimate of body fat, BMI is helpful for comparing populations, but consideration of factors such as age (older adults lose muscle and gain fat), fitness level (athletes have more muscle), and genetic variation (cutoff points are lower in Asian populations) may modify risk points for individuals.

Based on these criteria, The National Health and Nutrition Examination Survey (NHANES) 2007–2008 (Ogden 2010) reveals that in the U.S.

• 68% of adults older than 20 years are overweight, and 34% of that population is obese

• More men (72%) than women (64%) are overweight, but more women (36%) than men (32%) are obese

• Obesity rates are higher in minority populations, especially among women: 50% of non-Hispanic blacks, 43% of all Hispanics, and 33% of non-Hispanic white females are obese

• Overall, 6% of people are extremely obese, with a BMI ≥40 kg/m2

Data from the NHANES surveys (1976–1980 and 2003–2006) show that the prevalence of obesity has increased for children from 5.0% to over 17% during that period (CDC 2010).

BMI in childhood correlates significantly with BMI in adulthood (Ferraro 2003, Zhao 2011). Young people who are already obese at age 10–15 years are fast becoming the adults who continue to gain weight at the rate of 1.8–2.0 pounds per year between 20 and 40 years of age (Pi-Sunyer 2005). The problems associated with obesity are poised to worsen. Figure 1 helps show how obesity is becoming a worsening global problem.

Escalating Burden

As obesity rates rise, the negative consequences of the condition increase. The costs of obesity to society include impaired physical health, impaired mental well-being, and diverted financial resources.

Impaired Physical Health

Obese persons generally experience more health and mobility problems than do nonobese persons (CDC 2001, Adolfsson 2004). Although not everyone who is obese experiences more health problems than their leaner counterparts (NHLBI 2000), obesity does increase the risk for impaired well-being and for several major diseases.

The link between excess body fat and type 2 diabetes is especially clear. Despite different measures of fatness and different criteria for diagnosing type 2 diabetes, there is a consistent association between excess weight and type 2 diabetes across differing population groups, supporting the strength of this connection (WHO 2000). Colditz (1990) and Chan (1994) report that as many as 65–75% of the people diagnosed with type 2 diabetes would not have developed the disease if their BMI had remained ≤25 kg/m2. As a result, the explosive increase in obesity predicts an associated increase in type 2 diabetes. Some have referred to this link between obesity and diabetes as “diabesity” (Zimmet 2001, Astrup 2000).

Sources agree that the number of children (aged <20 years) diagnosed with type 2 diabetes has increased significantly in the past decade, but no data exist to document the number. Minority adolescents, especially if overweight, are those most likely to have type 2 diabetes. A CDC/NIDDK study, Search for Diabetes in Youth, is collecting data to learn more about the character, treatment, and impact of a diabetes diagnosis on children and youth (Mayer-Davis 2009).

Overweight and obesity now rank as the fifth leading global risk for mortality. In addition, 44% of the diabetes burden, 23% of the ischemic heart disease burden, and 7–41% of certain cancer burdens are attributable to overweight and obesity (WHO 2009). Table 1 outlines additional risks associated with obesity (WHO 2000).

Table 1—Relative Risk of Health Problems Associated with Obesity

Both an individual’s fat distribution (i.e., waist circumference) and amount of fat (i.e., BMI) predict health risks (IDF 2006). Abdominal obesity may predict type 2 diabetes more accurately than overall fatness (Pi-Sunyer 2004). (See chapter 7 for more information.)

In addition to the amount and distribution of fat, there is a cluster of disease risk factors that are particularly important to consider when treating overweight or obese individuals (Kahn 2005).

This constellation of interrelated risk factors is often called the metabolic syndrome, and it is strongly associated with obesity, cardiovascular disease, and diabetes. Indicators of metabolic syndrome include dyslipidemia, elevated glucose, hypertension, abdominal obesity, and insulin resistance. In combination, these conditions synergistically increase risk. To help identify and treat the underlying problems, sets of diagnostic criteria have been developed. The American Heart Association and the National Heart, Lung, and Blood Institute updated the widely-used National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) with minor modifications in 2005. The changes in criteria lower the threshold for diagnosis by

1. lowering the cutoff point for elevated blood glucose, and

2. considering a categorical cut point met with drug therapy as a risk factor (Grundy 2005).

The presence of three or more of the risk factors in Table 2 constitutes a diagnosis of metabolic syndrome.

Table 2—Diagnostic Criteria for Metabolic Syndrome

In 2006, the IDF published a worldwide definition of the metabolic syndrome for use in clinical practice. Criteria differ in requiring waist circumference as one of the three risk factors. IDF also offers ethnic-specific values for waist circumference as follows: Caucasian origin, ≥37 inches (≥94 cm) for men and >31.5 inches (>80 cm) for women; South Asian, Japanese, and Chinese origin, ≥35.5 inches (≥90 cm) for men and ≥31.5 inches (≥80 cm) for women (IDF 2006) (See www.idf.org/metabolic-syndrome for additional details).

Impaired Mental Well-Being

Societal and individual responses to obesity can impair psychological health, which in turn can perpetuate obesity. Prejudices from an unsupportive social environment and social stigmatization are likely to affect psychological health, employment, housing, and overall quality of life (Link 2001). Stigmatization of and discrimination against obese people have been documented in many areas of life, including employment, education, and health care (Puhl 2009). Furthermore, negative attitudes toward obesity by health care professionals can act as a barrier in clinical practice (Teixeira 2010).

Common negative stereotypes attributed to people who are obese include lack of willpower, laziness, ugliness, weak will, emotional and moral instability, as well as being responsible for or to blame for one’s weight (Crossow 2001, Friedman 2005, Puhl 2009). The risk for such prevalent negative social messages arises because of the ease with which such attitudes can be internalized; thus, an obese individual may perceive these messages as realistic descriptions of him- or herself (Bacon 2001, Rogge 2004). In response, obese individuals, and those of average weight who feel overweight or obese, may place unnecessary restrictions on important aspects of their lives, such as going to school, changing jobs, buying stylish clothes, dating, enjoying a sexual relationship, and seeking medical care (Robinson 1996).

Women (including those who seek standard treatment as well as more drastic weight-reduction methods, such as surgery) report impaired mental well-being more often than do men or those who do not seek treatment for obesity (Kolotkin 2002). There is an association between a history of weight fluctuation and impaired well-being regardless of body weight (Foreyt 1995).

Impaired mental well-being can precipitate excessive eating as a way of coping with feelings of anxiety, sorrow, and sadness, and thus contribute to obesity (Adolfsson 2002). Excessive eating could also be a coping strategy to deal with obesity-induced stigma (Puhl 2003).

Growing Economic Burden

As the prevalence of obesity increases, so does the cost of caring for its consequences (Stern 2005). Multiple authors present figures to illustrate the enormous cost of obesity to the health care system, employers, employees, the obese, and the general public.

In 2009, reported annual obesity costs to the health care system range from $147 billion (Finklestein 2010) to $228 billion (Englehard 2009). Because the consequences of obesity are most evident as people age, Medicare/Medicaid pays 50% of this cost (Barkin 2010). Obese employees are more expensive (higher insurance rates) and less productive (Finklestein 2010). Research shows obese employees earn less (Barkin 2010) and pay 42% more for health care than persons of normal weight (Weight-control Information Network 2010). Even nonobese workers pay higher premiums to help cover medical costs of their heavier colleagues (Englehard 2009).

As young people gain weight at an increasing rate, their futures, individually and corporately, will be increasingly limited by missed opportunities and by the resources spent to cope with the consequences of obesity. Obese people are often judged less capable and are less often chosen to join a group or perform a job. Physical mobility may limit activities, and health problems reduce available time and money.

WHO and the World Bank recognize that diet-related problems, such as obesity, type 2 diabetes, cardiovascular disease, hypertension, stroke, and various forms of cancer, significantly contribute to disability and premature death in both developing and newly developed countries. Such health problems are overwhelming budgets and absorbing funds from other more traditional public health concerns, such as malnutrition and infectious disease, and placing additional burdens on already overtaxed national health budgets. Obesity is one of the principal contributors to noncommunicable diseases. Given this impaired physical health and its associated economic burden on individuals and societies as a whole, obesity is clearly a risk factor that warrants global attention.