Weight and Physical Health - Is Obesity A Disease?, The Genetics Of Body Weight And Obesity, Health Risks And Consequences Of Overweight And Obesity

If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health

—Hippocrates c. 460–377 BC

During the twentieth century, advances in public health and medical care helped Americans to lead longer, healthier lives. Two important measures of the health of the population are infant mortality (death) rates and life expectancy at birth rates. Infant mortality rates significantly decreased and life expectancy increased by thirty years. Table 2.1 shows the decline in infant mortality between 1983 and 2001 as well as the slight increase in 2002, which probably represents a leveling off rather than a statistically significant rise in infant mortality. Table 2.2 shows the long-term upward trend in life expectancy as well as recent gains. In 2002 life expectancy at birth for the total population reached a record high of 77.3 years, up from 75.4 years in 1990. The CDC estimated that in 2005 life expectancy at birth had increased to 77.6 years.

As deaths from infectious diseases declined, mortality from chronic diseases, such as heart disease and cancer, increased. Table 2.3 displays the ten leading causes of death in the United States in 1980 and 2002. Overweight and obesity are considered contributing factors to at least four of the ten leading causes of death in 2002—diseases of the heart, malignant neoplasms (tumors), cerebrovascular diseases (diseases affecting the supply of blood to the brain), and diabetes mellitus. (Obesity also may be implicated in some deaths attributable to another leading cause of death—kidney disease or chronic renal failure, which are called nephritis, nephrotic syndrome, and nephrosis in Table 2.3.) Table 2.3 also reveals the rise of diabetes as a cause of death. In 1980 it was the seventh leading cause of death, claiming nearly 35,000 lives. By 2002 it rose to the sixth leading cause of death overall, the fifth leading cause of death among women, and the sixth leading cause of death among men. It was the underlying cause of over 73,000 deaths and was mentioned on the death certificates of more than twice as many additional deaths. Epidemiologists (scientists who study the occurrence and distribution of diseases and the factors that govern their spread) and medical researchers believe that the increasing prevalence of diabetes in the U.S. population and the resultant rise in deaths attributable to diabetes are direct consequences of the obesity epidemic in America.

Figure 2.1 reveals little change in the prevalence of overweight and obesity between the 1960s and 1980, and increasing prevalence of overweight and obesity in the two decades between 1980 and 2000. As Figure 2.1 shows, 65% of American adults were overweight during 1999–2002, including the 31% who were classified as obese. The prevalence of obesity varies somewhat by gender, race, and ethnicity. In 1999–2002 slightly more women (34%) than men (28%), and one-half of non-Hispanic black women, were obese. (See Figure 2.2.)

Overweight and obesity not only increase the risk of morbidity (disease) and mortality (death) but also the severity of diseases such as hypertension (high blood pressure), arthritis, and other musculoskeletal problems. Table 2.4 lists the health consequences that may result from overweight and obesity among adults and children. It also estimates the likelihood of these health consequences. For example, adults who are obese are twice as likely to suffer from high blood pressure as adults who are at a healthy weight

In 2005 S. Jay Olshansky and his colleagues at the University of Illinois suggested that the steady rise in life expectancy the U.S. enjoyed during the past two centuries might soon come to an end. The investigators used obesity prevalence data and previously published estimates of years of life lost from obesity to project life expectancy. Instead of using historical trends to forecast life expectancy, they calculated in reverse, assessing the TABLE 2.1 Infant, neonatal, and postneonatal mortality rates, by race and Hispanic origin of mother, selected years 1983–2002fall in death rates that would occur if all obese Americans had a normal weight. Their projections revealed that within fifty years, obesity is likely to reduce the average life expectancy in the United States by at least two to five years from its present 77.6 years. The impact of obesity and its health consequences on life expectancy was considered larger than cancer or heart disease (S. Jay Olshansky et al., "A Potential Decline in Life Expectancy in the United States in the 21st Century," New England Journal of Medicine, vol. 352, no. 11, March 17, 2005).

TABLE 2.1
Infant, neonatal, and postneonatal mortality rates, by race and Hispanic origin of mother, selected years 1983–2002
[Data are based on linked birth and death certificates for infants]
Race and Hispanic origin of mother	1983a	1985a	1990a	1995b	1998b	1999	2000b	2001b	2002b
	Infantc deaths per 1,000 live births
All mothers	10.9	10.4	8.9	7.6	7.2	7.0	6.9	6.8	7.0
White	9.3	8.9	7.3	6.3	6.0	5.8	5.7	5.7	5.8
Black or African American	19.2	18.6	16.9	14.6	13.8	14.0	13.5	13.3	13.8
American Indian or Alaska Native	15.2	13.1	13.1	9.0	9.3	9.3	8.3	9.7	8.6
Asian or Pacific Islander	8.3	7.8	6.6	5.3	5.5	4.8	4.9	4.7	4.8
Chinese	9.5	5.8	4.3	3.8	4.0	2.9	3.5	3.2	3.0
Japanese	5.6*	6.0*	5.5*	5.3*	3.4*	3.5*	4.5*	4.0*	4.9*
Filipino	8.4	7.7	6.0	5.6	6.2	5.8	5.7	5.5	5.7
Hawaiian	11.2	9.9*	8.0*	6.5*	9.9	7.0*	9.0	7.3*	9.6
Other Asian or Pacific Islander	8.1	8.5	7.4	5.5	5.7	5.1	4.8	4.8	4.7
Hispanic or Latinod,e	9.5	8.8	7.5	6.3	5.8	5.7	5.6	5.4	5.6
Mexican	9.1	8.5	7.2	6.0	5.6	5.5	5.4	5.2	5.4
Puerto Rican	12.9	11.2	9.9	8.9	7.8	8.3	8.2	8.5	8.2
Cuban	7.5	8.5	7.2	5.3	3.7*	4.6	4.6	4.2	3.7
Central and South American	8.5	8.0	6.8	5.5	5.3	4.7	4.6	5.0	5.1
Other and unknown Hispanic or Latino	10.6	9.5	8.0	7.4	6.5	7.2	6.9	6.0	7.1
Not Hispanic or Latino
Whitee	9.2	8.6	7.2	6.3	6.0	5.8	5.7	5.7	5.8
Black or African Americane	19.1	18.3	16.9	14.7	13.9	14.1	13.6	13.5	13.9
	Neonatalc deaths per 1,000 live births
All mothers	7.1	6.8	5.7	4.9	4.8	4.7	4.6	4.5	4.7
White	6.1	5.8	4.6	4.1	4.0	3.9	3.8	3.8	3.9
Black or African American	12.5	12.3	11.1	9.6	9.4	9.5	9.1	8.9	9.3
American Indian or Alaska Native	7.5	6.1	6.1	4.0	5.0	5.0	4.4	4.2	4.6
Asian or Pacific Islander	5.2	4.8	3.9	3.4	3.9	3.2	3.4	3.1	3.4
Chinese	5.5	3.3	2.3	2.3	2.7	1.8	2.5	1.9	2.4
Japanese	3.7*	3.1*	3.5*	3.3*	2.5*	2.8*	2.6*	2.5*	3.7*
Filipino	5.6	5.1	3.5	3.4	4.6	3.9	4.1	4.0	4.1
Hawaiian	7.0*	5.7*	4.3*	4.0*	7.2*	4.9*	6.2*	3.6*	5.6*
Other Asian or Pacific Islander	5.0	5.4	4.4	3.7	3.9	3.3	3.4	3.2	3.3
Hispanic or Latinod,e	6.2	5.7	4.8	4.1	3.9	3.9	3.8	3.6	3.8
Mexican	5.9	5.4	4.5	3.9	3.7	3.7	3.6	3.5	3.6
Puerto Rican	8.7	7.6	6.9	6.1	5.2	5.9	5.8	6.0	5.8
Cuban	5.0*	6.2	5.3	3.6*	2.7*	3.5*	3.2*	2.5*	3.2*
Central and South American	5.8	5.6	4.4	3.7	3.6	3.3	3.3	3.4	3.5
Other and unknown Hispanic or Latino	6.4	5.6	5.0	4.8	4.5	4.8	4.6	3.9	5.1
Not Hispanic or Latino
Whitee	5.9	5.6	4.5	4.0	3.9	3.8	3.8	3.8	3.9
Black or African Americane	12.0	11.9	11.0	9.6	9.4	9.6	9.2	9.0	9.3
	Postneonatalc deaths per 1,000 live births
All mothers	3.8	3.6	3.2	2.6	2.4	2.3	2.3	2.3	2.3
White	3.2	3.1	2.7	2.2	2.0	1.9	1.9	1.9	1.9
Black or African American	6.7	6.3	5.9	5.0	4.4	4.5	4.3	4.4	4.5
American Indian or Alaska Native	7.7	7.0	7.0	5.1	4.4	4.3	3.9	5.4	4.0
Asian or Pacific Islander	3.1	2.9	2.7	1.9	1.7	1.7	1.4	1.6	1.4
Chinese	4.0	2.5*	2.0*	1.5*	1.3*	1.2*	1.0*	1.3*	0.7*
Japanese	*	2.9*	*	*	*	*	*	*	*
Filipino	2.8*	2.7	2.5	2.2	1.6	1.9	1.6	1.5*	1.7
Hawaiian	4.2*	4.3*	3.8*	*	*	*	*	3.7*	4.0*
Other Asian or Pacific Islander	3.0	3.0	3.0	1.9	1.8	1.8	1.4	1.6	1.4