Anorexia in older persons: epidemiology and optimal treatment.

Anorexia and weight loss are common findings in older persons. Over a life-time, normal persons decrease their food intake to counterbalance the decrease in physical activity and resting metabolic rate that occurs with aging. This physiological anorexia of aging increases the propensity to develop pathological anorexia and weight loss when an older person develops either a medical or psychological illness. The physiological anorexia of aging is due to a decreased opioid (dynorphin) feeding drive and an increase in the satiating effect of the gastrointestinal hormone, cholecystokinin. Nitric oxide deficiency may play a role in the early satiation commonly seen in older persons. A variety of social, psychological and medical conditions can lead to pathological anorexia. Depression is the most common cause of weight loss and anorexia in older persons. A number of conditions such as cancer and rheumatoid arthritis produce their anorectic and wasting effects by releasing cytokines. An idiopathic pathological senile anorexia has been characterised which also appears to be a cytokine-dependent syndrome. Early screening for malnutrition is a cornerstone of the management of anorexia; the Mini Nutritional Assessment is a well validated screening tool available for this purpose. Aggressive use of caloric supplements, enteral tube feeding and peripheral parenteral nutrition all have a role in the early management of anorexia. Numerous drugs (growth hormone, megestrol, cyproheptadine, tetrahydrocannabinol, anabolic steroids, prokinetic agents and antidepressants) have been utilised to treat the anorexia of aging with varying success.