74 year age range remains substantial however. Data from the Third National Health and Nutrition Examination Survey (NHANES III) (1988–1994) indicate that in the 65 to 74 year age range, approximately 34 percent of women and 44 percent of men are considered overweight (BMI 25 to 29.9) and an additional 27 percent of women and 24 percent of men are considered obese (BMI greater than or equal to 30) (NCHS, 1999). Older African-American and poor women have higher rates of obesity.

An important characteristic of adiposity accompanying aging is the distribution of fat, which is more likely to be centrally distributed in older persons. This central obesity is commonly associated with insulin resistance, hypertension, and lipid abnormalities (Schwartz, 1997).

Data on the risks associated with obesity in older persons are less consistent than for those with undernutrition. A substantial body of evidence links overweight to hypertension, dyslipidemia, heart disease, insulin resistance and diabetes, cholelithiasis, respiratory impairment, gout, and osteoarthritis (Pi-Sunyer, 1993). However, the relation between obesity and occurrence rates of specific diseases or overall mortality in persons over 65 years has received limited study. There is some evidence that the obesity-associated relative risk of disease occurrence is less in older than in younger persons. Although some data support the association of obesity and premature mortality in older persons (Calle et al., 1999), this evidence is inconsistent. Several cohort studies have demonstrated that a high BMI does not predict mortality, and, indeed, may even be protective against early death in older persons (Diehr et al., 1998; Fried et al., 1998; Stevens et al., 1998). In addition, overweight has been identified as a protective factor for hip fracture (independent of its relation to bone density) (Greenspan et al., 1994). However, other studies indicate that obesity is related to the development of functional impairment (Galanos et al., 1994; Vita et al., 1998). Thus, perhaps unique to the geriatric population, benefits versus risks of weight reduction should be analyzed on an individual basis. A recent Institute of Medicine report, Weighing the Options: Criteria for Evaluating Weight-Management Programs, reviewed the health benefits of weight loss in obesity (IOM, 1995). For this reason and those addressed above, obesity is not addressed separately, but only as it relates to specific conditions (e.g., hypertension, dyslipidemia, diabetes).

Although energy undernutrition and protein–energy undernutrition are much less common, these disorders have major prognostic importance. Conditions of energy undernutrition include adult marasmus (energy undernutrition), in which normal serum proteins are maintained, and adult kwashiorkor (protein–energy undernutrition).