Karen L. Smith, MSc, Kunin Lunenfeld Applied Research Unit, Baycrest and Department of Nutritional Sciences, University of Toronto, Toronto, ON.
Carol Greenwood, PhD, Kunin Lunenfeld Applied Research Unit, Baycrest and Department of Nutritional Sciences, University of Toronto, Toronto, ON.
Helene Payette, PhD, Director, Research Center on Aging, Health & Social Services Centre - University Institute of Geriatrics of Sherbrooke, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC.
Shabbir M.H. Alibhai, MD, MSc, Division of General Internal Medicine & Clinical Epidemiology, University Health Network; Geriatric Program, Toronto Rehabilitation Institute; Departments of Medicine and Health Policy, Management and Evaluation, University of Toronto, Toronto, ON.

Unintentional weight loss is common among older adults and is associated with significant adverse health outcomes, increased mortality, and progressive disability. The diagnosis is often associated with an underlying illness; however, in as many as one in four older adults with unintentional weight loss, no obvious medical cause can be identified. A variety of nonpharmacologic interventions may improve energy intake and lead to weight gain. The most common approach to the treatment of weight loss among older adults is consumption of high-energy/protein oral supplements between meals as a means of increasing daily energy intake. Involving other health professionals, including a dietitian, may be helpful in the assessment and management plan. In addition, a number of pharmacologic treatments have been investigated, but the potential benefit of these treatments remains unclear.
Key words: weight loss, older adults, malnutrition, oral nutritional supplementation, megestrol.

Krupa Shah, MD, MPH, Geriatric Fellow, Washington University at St. Louis, Division of Geriatric and Nutritional Science, St. Louis, MO, USA.
Dennis Villareal, MD, Associate Professor, Washington University at St. Louis, Division of Geriatric and Nutritional Science, St. Louis, MO, USA.

Obesity is associated with significant morbidity and mortality. In older adults, obesity can exacerbate declining physical function and quality of life that often accompanies aging, and can cause frailty. The value of treatment for obesity in older adults has been under debate because of the uncertain effectiveness of obesity therapies in this population as well as the potentially harmful effects of weight loss. However, current evidence shows that weight-loss treatment improves physical function and quality of life, and also eases the medical complications associated with obesity in older adults. Therefore, moderate weight loss that minimizes muscle and bone loss is recommended for obese older adults who have functional decline or medical complications.
Key words: obesity, body mass index, metabolic syndrome, weight loss, lifestyle modification.

Karen L. Smith, MSc, Kunin Lunenfeld Applied Research Unit, Baycrest and Department of Nutritional Sciences, University of Toronto, Toronto, ON.
Carol Greenwood, PhD, Kunin Lunenfeld Applied Research Unit, Baycrest and Department of Nutritional Sciences, University of Toronto, Toronto, ON.
Helene Payette, PhD, Research Center on Aging, Health & Social Services Center - University Institute of Geriatrics of Sherbrooke, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC.
Shabbir M.H. Alibhai, MD, MSc, Division of General Internal Medicine & Clinical Epidemiology, University Health Network; Geriatric Program, Toronto Rehabilitation Institute; Departments of Medicine and Health Policy, Management and Evaluation, University of Toronto, Toronto, ON.

Unintentional weight loss is a common problem among community-dwelling older adults. Although a slight decline in body weight is considered a normal part of the aging process, clinically significant weight loss (>5% of usual body weight) has harmful consequences on functional status and quality of life, and is associated with excess mortality over a three- to twelve-month period. A variety of physical and psychological conditions, along with age-related changes, can lead to weight loss. In up to one-quarter of patients, there is no identifiable cause. A rational approach to clinical investigation of these patients can facilitate arriving at a diagnosis and minimize unnecessary diagnostic procedures.
Key words: weight loss, older adults, mortality, epidemiology, diagnosis.

Isabelle J. Dionne, PhD, Faculty of Physical Activity and Sports, University of Sherbrooke; Research Centre on Aging, Geriatric Institute of Sherbrooke University, Sherbrooke, QC.
Martin Brochu, PhD, Faculty of Physical Activity and Sports, University of Sherbrooke; Research Centre on Aging, Geriatric Institute of Sherbrooke University, Sherbrooke, QC.

There is a high prevalence of obesity in older adults up to the age of 80. While women generally gain body weight during the menopausal transition, men tend to accumulate an excess of fat mass earlier in life for as yet unknown reasons. Consequently, an increasing proportion of older adults are now obese. Obesity’s association with metabolic diseases such as metabolic syndrome, type II diabetes, and cardiovascular disease is widely recognized. However, recent evidence shows that, in older adults, obesity is also related to functional impairment and decreased quality of life. This review addresses the actual prevalence and definition of obesity in older adults, the energy-balance equation, and the known consequences of obesity. Finally, the heterogeneity of obesity in older adults regarding its association with metabolic diseases and functional capacity will be discussed, as well as how obesity treatment should be conducted in this population.

Key words: obesity, metabolic syndrome, diabetes, weight loss, impaired functional capacity.

The "Nine Ds" of Determining the Cause of Weight Loss in the Elderly

David M. Kaplan, MScHA

Weight loss in the elderly should always be a great concern for the clinician because it can be an indicator of malnutrition. Involuntary weight loss has been shown to be highly predictive of morbidity and mortality.¹ All physicians who treat geriatric patients need to have a framework for identifying and evaluating weight loss in this patient population. One Canadian study found that 40% of elderly persons receiving home care services reported involuntary weight loss over a period of one year.² This practical approach to involuntary weight loss in the elderly will begin with a definition and then present a simple and organized approach to diagnosis and evaluation.

Definition and Risk Factors
Weight loss in the elderly becomes worrisome when the patient has involuntarily lost five percent of their body weight over a six-month period.³ Social Isolation has been identified as a risk factor for weight loss. While the mechanisms are not clearly understood, it is thought that poor physical functioning may be linked to a decrease in social support.⁴ Social isolation has been demonstrated to be detrimental to health and health outcomes.^3,4,5 Sensory decline, poor oral hygiene, disease, polypharmacy, drug-nutrient interactions, poverty, and alcohol abuse have been found to be risk factors for involuntary weight loss in the geriatric population.

Approach to Weight Loss
Before the clinician adopts an approach to determine the cause of weight loss in a specific patient, she must first be astute enough to perceive a problem. Recognizing weight loss in the elderly can often be problematic. Our pediatric colleagues place great importance on following and charting weight and height parameters in all their patients. It is best to follow their example in this regard. Geriatricians, family physicians, and other primary care providers should, at the very least, record the patient's weight and height at every visit. By adopting this practice ritual, they will become aware of subtle weight loss in their elderly patients.

Once established, involuntary weight loss can be handled by utilizing a broad-approach differential diagnosis. Bianchi divides weight loss into three possible, but not mutually exclusive, etiologies.⁵ Of the three basic causes of weight loss, decreased intake (table 1) is the most common in the elderly. The second cause, increased fluid-nutrient loss (table 2), is caused predominantly by malabsorptive disorders and by diabetes. Lastly, states of excess metabolic demand (table 3) resulting from gastrointestinal, genitourinary and breast carcinomas are also a basic cause of weight loss.

TABLE 1 CAUSES OF DECREASED FOOD INTAKE LEADING TO INVOLUNTARY WEIGHT LOSS
Mechanism of weight loss	Example
Disease Gastrointestinal Malignancy Eating Disorders Infection Systemic diseases	Peptic Ulcer, Cholelithiasis GI, Ovarian Anorexia, Bulimia Nervosa HIV
Depression Dysphagia Dysgeusia Dentition Dysfunction Dementia	Primary illness or concurrent with failing medical condition May be caused by disease May be caused by disease Poor Dentition Primary illness
Drugs Substance Abuse Medications	Alcohol Beta-blockers Anticholinergics Benzodiazepines Neuroleptics SSRIs Tricyclic antidepressants
Poverty	Unable to afford food
Social Isolation	Multiple mechanisms

A second, and perhaps, more practical approach to a differential diagnosis of weight loss in this specific population, is the "Nine Ds of weight loss in the elderly."⁷ Robbins first identifies whether the cause of weight loss is due to acute or chronic disease. The different diseases that lead to weight loss have been discussed above and in the accompanying tables. Depression has also been implicated in weight loss and health outcomes. Depression is linked to social isolation and, therefore, depression affects health outcomes.^3,5 Depression in the elderly is correlated to lower socioeconomic status, female gender, older age, martial status, frequency of visits to physicians, lower functional status, and poor self-reported health.^5,7 Clinicians must realize that these patients often present with physical, rather than emotional, complaints.⁴ While it is the most common psychiatric illness in this population, it is under-diagnosed and under-treated.

Diarrhea, dysphagia, dysgeusia (impaired taste), and abnormal dentition are obvious causes of weight loss in any population and must be kept in mind while examining the patient. Numerous studies have linked dementia to weight loss in the elderly.⁴ One of the outcomes of dementia, dysfunction (problems in physical, cognitive and psychosocial function), is itself an independent cause.4 Food shopping, and the preparation and eating of food are integral parts of our daily life. And yet, Markson reports that 23% of older people in the community have health-related difficulties with activities of daily living (ADLs) such as bathing, dressing, feeding, and using the bathroom.⁸ Moreover, 28% of the same population has difficulties with independent activities of daily living (IADL) (using the telephone, shopping, banking, laundry, and transportation).⁸ Clearly, patients who have had a decline in their functional ability are at risk for involuntary weight loss.

Whether due to a single pharmaceutical agent or to polypharmacy, drugs can also cause weight loss in the elderly.⁴ Beta-blockers and anticholinergic agents cause cognitive changes, which lead to functional decline. Narcotics, benzodiazepines, neuroleptics, and selective serotonin reuptake inhibitors (SSRIs) can produce anorexia. Lastly, use of tricyclic antidepressants to treat depression can cause dysgeusia and dry mouth. Now that a general approach to diagnosing the cause of weight loss in the elderly patient has been described, we can begin to illustrate a more individualized approach to a particular patient in the office.

TABLE 2 CAUSES OF INCREASED FLUID/NUTRIENT LOSS LEADING TO INVOLUNTARY WEIGHT LOSS
Mechanism of weight loss	Example
Disease Malabsorption Recurrent vomiting Fistulous drainage Pancreatic	Celiac disease
Insufficiency Infection Inflammatory bowel disease	Giardiasis Crohn's disease
Drugs Medications	Cholestyramine, laxatives

The Patient Encounter
The medical interview is fundamental to the patient encounter. The best method of initiating an investigation of a patient who has had clinically noted weight loss is to take a complete history. Specifically, one should focus on determining the following: First, what is the patient's daily oral intake; secondly, are there symptoms characteristic of malabsorptive conditions or malignancy; thirdly, is there a history of heart, lung, or kidney failure. As explicated previously, a depression-screening exam may also be beneficial in the work-up of a patient with involuntary weight loss. As is usually the case, one should conclude the history with a complete review of systems to elicit whether the patient may be having any additional symptoms.

The physical exam is guided by what one uncovers during the interview. While working up these patients from a general standpoint, the physical exam should include the measurement of vital signs, the patient's weight and height, and a calculated body-mass index (BMI: weight(kg)/height (m)²). Healthy, elderly people should have stable weights and a BMI higher than 23 kg/m². One should look for evidence of dementia by doing cognitive tests such as repeated Folstein Mini-Mental State Examinations. The presence of lymph nodes, evidence of previous chest or abdominal surgery, abdominal masses, abdominal distention, ascites, or organomegaly should be noted. A digital rectal exam should also be performed along with fecal occult blood testing. Next, a full musculoskeletal exam should be conducted to observe evidence of osteoarthritis, which could be affecting the patient's ADLs and IADLs. Lastly, a screening neurological exam should be done to elicit any focal neurological lesions.

Armed with the data from the complete, focused history and physical, the basic laboratory screening tests may include a complete blood count, electrolytes, blood glucose, urinalysis, liver and renal function tests, calcium, thyroid function, hemoccult stool tests, and a chest radiograph. The special tests, which may be necessary based on history and physical exam findings include: ESR, HIV test, blood cultures, upper GI series, esophagealgastroduodenoscopy, and colonoscopy.^3,7 A CT scan or ultrasound study may be indicated to investigate abdominal masses or abscesses.

TABLE 3 CAUSES OF EXCESS METABOLIC DEMAND LEADING TO INVOLUNTARY WEIGHT LOSS
Mechanism of weight loss	Example
Disease Hyperthyroidism Tumour of adrenal gland Malignancy Fever/infection Systemic disease	Pheochromocytoma Disseminated metastatic Malaria, TB, HIV
Depression/dementia and other psychiatric disorders Trauma Excessive exercise	Mania Burns

Treatment
While the purpose of this article was to elucidate an approach to the patient who presents with involuntary weight loss, the final section will briefly describe the general management of these patients. If the results of the basic screening do not reveal an underlying disease, a waiting period to see how the patient fares would be prudent; serious disease will likely, if present, reveal itself within half a year.³ Once the cause of the weight loss is evident, treatment is based on the underlying medical or psychological conditions. One should continue to monitor height and weight throughout the course of treatment. A reassessment of the patient's medications is also warranted. Finally, the proper use of community resources (Meals on Wheels, Assisted living, nursing homes), a dietician, social worker, and an occupational therapist should also comprise part of a comprehensive treatment plan for these patients.

Summary
Involuntary weight loss, defined as a five percent of body weight reduction over a six-month period, has been shown to be a cause of poor health outcomes in the elderly patient. This approach highlighted the necessity for clinicians to be cognizant of the many etiologies of weight loss in this population. A good history and physical followed by appropriate laboratory tests is necessary in order to diagnose and successfully develop a comprehensive treatment plan.

References

1. Wallace, JI, Schwartz RS. Involuntary Weight Loss in Elderly Outpatients: Recognition, Etiologies, and Treatment. Clinics in Geriatric Medicine: Failure to Thrive in Older People 1997;13(4):717-736.
2. Payette H, Gray-Donald K. Risk of malnutrition in an elderly population receiving home care services. Facts and Research in Gerontology 1994;2(suppl):71-85.
3. Verdery RB. Clinical evaluation of Failure to Thrive in Older People. Clinics in Geriatric Medicine: Failure to Thrive in Older People 1997;13(4):717-736.
4. Markson, EW. Functional, Social, and Psychological Disability as Causes of Loss of Weight and Independence in Older Community-Living People. Clinics in Geriatric Medicine: Failure to Thrive in Older People 1997;13(4):717-736.
5. Berkman LF, Berkman CS, Kasl S et al. Depressive symptoms in relation to physical health and functioning in the elderly. Am J Epidemiol 1986;124:372-388.
6. Bianchi A, Toy EC, Baker B III. "The Evaluation of involuntary weight loss." Primary Care Update Ob/Gyns 1998; 5:263-267.
7. Robbins LJ. Evaluation of weight loss in the elderly. Geriatrics 1989;44:31-37.
8. American Association of Retired Persons and Administration on Aging, U.S. Department of Health and Human Services: A Profile of Older Americans, 1996. Washington, DC, Program Resource Department, American Association of Retired Persons, 1996.