Overweight and Health

The effects of excess body weight are widespread and raise a variety of concerns relevant to the health and performance of members of the military. The major comorbidities associated with obesity and the implications of these comorbidities for the military services are briefly reviewed below. (For an extensive review of the major health effects of overweight, see Bray, 1996 and Must et al., 1999).

Overweight and obesity have also been associated with a variety of adverse social and economic consequences. These appear to be more significant among women than among men. For example, one study showed that obese women completed fewer years of school, married less frequently, and had lower earnings than women who were not obese (Gortmaker et al., 1993). Although these data were obtained before obesity achieved its current prevalence, they suggest a variety of long-term effects on material and psychological well-being.

Obesity also has a variety of adverse physiological effects. The major comorbidities associated with obesity are shown in Box 1-1. It has been observed that the prevalence of type 2 diabetes mellitus, hyperlipidemia, hypertension, and heart disease increased with the severity of obesity, and that prevalence ratios were generally greater in younger than in older adults (Must et al., 1999). Approximately 70 percent of overweight individuals have at least one of these complications, and over 30 percent have two or more (Must et al., 1999).

BOX 1-1

Consequences of Adult Obesity. Psychosocial consequences Low self-esteem

Obesity is also associated with increased mortality rates. In one study by Allison and colleagues (1999), obesity-related mortality was estimated from data collected in five prospective cohort studies. The estimated number of annual deaths in the United States attributable to obesity ranged from 280,000 to 325,000, depending on whether the analysis controlled for smoking rates. Approximately 80 percent of the deaths attributable to overweight occurred in persons with a BMI ≥ 30, which is the lower limit for obesity. The estimates of the effects of obesity on mortality rates are quite consistent with earlier published estimates by McGinnis and Foege (1993), who suggested that approximately 300,000 deaths per year could be attributed to poor diet and inactivity patterns, which are the major contributors to obesity.

The comorbidities associated with obesity substantially increase health care costs. For example, total costs associated with obesity-related type 2 diabetes mellitus; coronary heart disease; hypertension; gall bladder diseases; breast, endometrial, and colon cancer; and osteoarthritis in 2000 were estimated at almost $117 billion per year (HHS, 2001). Approximately half of these costs were medical costs directly associated with the treatment of obesity and its comorbidities; the other half were indirect costs associated with increased absenteeism and decreased economic productivity. In one managed care organization, obesity was clearly associated with increased outpatient visits, inpatient days, and use of pharmacy and radiology services (Quesenberry et al., 1998).

Upper Body Adiposity

BMI does not account for all of the increased morbidity associated with obesity; the distribution of adipose tissue also influences the risk of excess weight. Upper body, or more specifically, visceral adipose tissue, carries a higher morbidity risk than adipose tissue deposited in the subcutaneous compartments of the buttocks, thighs, and lower extremities (NHLBI, 1998).

Individuals with upper body adiposity may be predisposed to other obesity-related conditions such as insulin resistance, glucose intolerance, dyslipidemias, and high blood pressure, often referred to collectively as “Syndrome X” or the “metabolic syndrome” (Bjorntorp, 1992a, 1992b; Hjermann, 1992). Factors that increase the deposition of visceral adipose tissue include male gender, lack of physical activity, alcohol use, and smoking (Emery et al., 1993; Han et al., 1998). The distribution of upper body adipose tissue may also impact appearance, which is relevant to military standards.

In order to clinically evaluate adipose tissue distribution, an individual's waist circumference (W) is evaluated as a measure of visceral obesity, with W > 102 cm (40 in) in men and W > 88 cm (35 in) in women considered high risk for heart disease (NHLBI, 1998). Waist circumference measurements are supplementary to BMI when diagnosing overweight and obesity; waist measurements lose their predictive value for increased risk of heart disease with a BMI ≥ 35.

Demographics

There are a number of important demographic differences between the military and the general population. While the general population is fairly evenly split between genders (49.1 percent men versus 50.9 percent women) (U.S. Census Bureau, 2003), the military is largely comprised of men (85 percent versus 15 percent women) (Personal communication, B. Maxfield, Office of the Deputy Chief of Staff for Personnel, March 7, 2003), although this varies somewhat with the individual services. For example, the Air Force is comprised of 80.6 percent men and 19.4 percent women, while the Marine Corps is comprised of 94 percent men and only 6 percent women (Personal communication, B. Maxfield, Office of the Deputy Chief of Staff for Personnel, March 7, 2003).

Ethnic demographics also differ somewhat between the general U.S. population and the active-duty military population. Although the proportion of Whites, American Indian/Alaska Natives, and Asian American/Pacific Islanders in the military tend to reflect the general U.S. population, the percentage of Black men is higher in the military than in the general population (17.7 percent vs. 12.3 percent), while the percentage of Hispanic men is lower (9 percent vs. 13.4 percent) (Tables 1-1 and 1-2). There is also a notable difference in the distribution of ethnicity by gender in the military compared with the general population. A greater proportion of women in the military are ethnic minorities. For example, 41.7 percent of Army women are Black and 9.7 percent are Hispanic, while 21 percent of Marine Corps women are Black and 16.6 percent are Hispanic (Table 1-2).

TABLE 1-1

Percent Gender and Race/Ethnicity of the U.S. Population Compared with the Department of Defense (DOD) Population.

TABLE 1-2

Percent Gender and Race/Ethnicity of the Military Branches.

Another significant demographic that differs between the general U.S. population and the active-duty military population is that of age. While only 31.5 percent of the U.S. population is between the ages of 18 and 40 years (U.S. Census Bureau, 2003), this age range encompasses nearly 80 percent of the active-duty military population.

Health and Fitness

Table 1-3 presents a comparison of the percentage of the general population (Flegal et al., 2002; Freedman et al., 2002) versus the military service population in four BMI categories. While the percentage of military men and women in the BMI category of 25 to 29.9 is higher than the general population, the percentage in the BMI category of ≥ 30 is much lower. Also, the percentage of women with a BMI of less than 25 is higher for military women than for civilian women. The high prevalence of military personnel in the 25 to 29.9 BMI category reflects the fact that until late 2002, the military maximum weight-for-height standards were not based on the standard BMI categories (NHLBI, 1998).

TABLE 1-3

Percent Body Mass Index (BMI) of Military Branches by Gender Compared with the General U.S. Population.

The military environment has both positive and negative aspects associated with it in terms of maintaining physical fitness and healthy weight. On the positive side, military personnel have ready access to health care providers. In addition, DOD has the potential for centralized, longitudinal record-keeping on all active duty personnel, the unusual ability to provide incentives and consequences for weight change, and the potential ability to modify environmental factors that are important for weight control. Possible negative aspects of the military environment include a very mobile population and the potential for inappropriate weight-loss activities fostered by the need to meet weight, fitness, and fatness standards.

Weight and Body Composition

At present, all active-duty personnel must be weighed and assessed for physical fitness annually or semiannually. If an individual's weight exceeds the maximum for his or her height according to the screening tables for his or her service, the individual is referred for a second-tier assessment (a determination of percent body fat), to ascertain whether the increased weight is due to fat or to lean tissue. In addition, a commander may order an individual in his or her command to be weighed at any time if the commander believes that the individual presents an overweight appearance in uniform. Personnel whose percent body fat exceeds the limit for their service and who do not qualify for a medical waiver are referred to a weight-management program (at the discretion of the commander), which carries professional consequences.

Administration of military weight-management programs is left to each service individually. These programs, which are described in greater detail in Chapter 2, generally require a single visit to a health professional followed by regular weigh-ins until weight and/or body fat goals are reached. Individuals are required to demonstrate continuing progress toward these goals by losing a prescribed number of pounds per month. Failure to show continued progress in weight loss or continued failure to comply with body-fat standards without a medical waiver can result in separation from the service. Similar attention is not devoted to personnel who are underweight.

Appearance

The DOD appearance standard is articulated by DOD (1995) Directive 1308.1, DOD Physical Fitness and Body Fat Programs. This policy is shared, but described slightly differently, by each of the service branches. According to the Directive, “maintaining desirable body composition is an integral part of physical fitness, general health, and military appearance” (p. 2), and the first line of body composition evaluation is by weight-for-height and appearance. For example, according to Army Regulation 600-9 (U.S. Army, 1987), one of the two goals of military weight standards is for soldiers to present a physical appearance in uniform “which is neat and trim.” The regulation goes on to describe the standard further by emphasizing that “excessive body fat connotes a lack of personal discipline, detracts from military appearance, and may indicate a poor state of health, physical fitness, or stamina.” No objective criteria (rating scales) have been associated with the appearance standard as it is enforced, although development of objective criteria has been recommended previously (IOM, 1992a, 1998).

Although appearance is associated slightly with percent body fat, it is associated more significantly with abdominal circumference (Hodgdon et al., 1990; U.S. Army, 1987; Vogel and Friedl, 1992). Army and Marine Corps personnel must supply recent photos of themselves to their promotion boards (this practice has been eliminated by the Air Force and Navy), but appearance judgments can be rendered by commanding officers at any time. When these judgments involve a suspicion of overweight (as opposed to an untidy uniform or other details of appearance), the individual must be weighed and may be required to have a body-fat determination and enter a weight-management program if standards are exceeded. In essence, the Directive considers appearance as important as weight-for-height standards, but it does not provide any objective criteria for assessing appearance. Instead, the Directive defers implementation of the policy to the individual services, which in turn defer to the individual units to establish criteria and implement the policy. This results in uneven application of the policy among units and across the services.

The relative role that appearance should play in relation to weight and body-fat programs in the military is a multifaceted issue. The military embraces a policy on appearance for several psychosocial reasons:

• It is perceived to be an indication of fitness.
• It may affect how the general public views the military.
• The appearance of military personnel is believed by some to be a factor in esprit de corps (Bauer et al., 1976; USMC, 1995).
• It may have some impact on how a country's military is perceived internationally.

The issue of appearance also influences the individual's self-esteem and acceptance by peers.