Anorexia of Aging
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Annals of Long-Term Care: Clinical Care and Aging. 19(10):18-24.
Angela Champion, BSN, RN
As people age, they become less active and normal physiologic changes cause a shift in body composition, with an increase in proportion of body fat and a decrease in lean muscle mass and extracellular fluid mass.1 The body typically responds to the decrease in energy needs with a desire for fewer calories. This predisposes older adults to anorexia of aging, a syndrome associated with unplanned weight loss and protein-energy malnutrition (PEM).2,3 The Centers for Medicare & Medicaid Services (CMS) defines significant unplanned or undesired weight loss as a 5% decline in body weight over 1 month, 7.5% over 3 months, and 10% over 6 months (Table 1).4 Various physiologic, pathologic, psychologic, and sociologic factors (eg, depression, loss of social networks, chronic illness, medications) increase the risk of anorexia of aging and resultant malnutrition.
Although it is widely recognized that maintaining a well-balanced and nutritious diet plays a vital role in maintaining good health during the aging process, malnutrition is becoming increasingly prevalent among the elderly population. Despite its prevalence, undernutrition—defined as protein-energy deficiency that is reversed solely by the administration of nutrients5—often goes undiagnosed in the elderly. Undernutrition is associated with an increased risk of mortality and morbidity, including frailty, pressure ulcers, impaired wound healing, dehydration, and functional decline.4 Failure to assess long-term care (LTC) residents for nutritional status and to document efforts to correct avoidable cases of undernutrition can result in deficiency citations from CMS for Tag F325.4
In addition to discussing the causes of anorexia of aging, this article reviews three validated instruments that are useful for assessing the nutritional status of geriatric patients. Interventions are also examined, with conclusions drawn from the literature about their effectiveness in addressing this syndrome. Understanding why some elderly people eat less as they get older, to the point where they experience unhealthy weight loss and PEM, will help healthcare providers learn how to assess for risk factors associated with anorexia of aging.
Prevalence of Protein-Energy Malnutrition
Elderly individuals often consume smaller meals, eat more slowly, drink less, and take fewer snacks between meals, all of which contribute to a reduction in calorie intake.6,7 One study reported a 25% decrease in daily calorie consumption from 40 to 70 years of age.8 Another study comparing differences in calorie consumption between individuals aged 25 years and 70 years found that older men’s daily caloric intake dropped by 1000 to 1200 kcal and older women took in 600 to 800 kcal less per day.5
A decline in activity and energy expenditure over time means fewer calories are needed to maintain body weight—one study9 estimated that an adult’s daily energy use declines 100 kcal each decade of life—and this helps balance the decrease in calories consumed. Any factor that further affects eating habits or increases energy requirements, however, can upset this balance, leading to significant weight loss or an unsafe decline in body mass index (BMI) and undernutrition.
In developed countries, approximately 85% of LTC residents, between 23% and 62% of hospitalized elderly patients, and 15% of community-dwelling older adults suffer from malnutrition.10,11 A recent meta-analysis of geriatric conditions commissioned by the US Preventive Services Task Force (USPSTF) noted that the lack of a universal standard for diagnosing malnutrition in the elderly makes it difficult to assess its prevalence.12 The USPSTF study determined that older African Americans were significantly more likely than white people to experience unintended weight loss; and while the authors found no difference in the risk of unintended weight loss between Hispanics and non-Hispanics, older Hispanic women were significantly more likely to have poor nutritional scores than older women who were not Hispanic (30% vs 17%, respectively).12
In the community and LTC settings, many age-related physiologic changes,medical conditions, medication use, mental health issues, and social factors contribute to an increased risk of anorexia of aging (Table 2[click thumbnail]). It has been reported that more than two-thirds of LTC residents aged ≥65 years voluntarily restrict their diet and reduce calorie consumption.7 Some factors may be modifiable, whereas others are not. In those cases, additional measures are needed to halt and hopefully reverse unintended weight loss and undernutrition.