Age, anemia, and fatigue.

Many conditions that would not be considered normal in a younger population are routinely accepted in older people as a part of so-called "normal" aging. Among these conditions are many chronic and debilitating conditions such as chronic pain, insomnia, weakness, fatigue, and anemia. This article reviews current evidence regarding the relationships among age, fatigue, weakness, anemia, and erythropoiesis. Anemia in the elderly is important because it can lead to weakness, fatigue, limitations in activity, and may increase cardiovascular risk. Recent studies of the effect of erythropoietin in an aging population support the hypothesis that anemia is associated with pathologic factors and not with normal aging. While older individuals admitted to hospitals are more likely to be anemic, these same individuals have a bone marrow mass and numbers of cultured progenitor cells that are similar to that of the younger population; therefore, the predicted response to erythropoietin, and thus the function of the bone marrow and cellular progenitors, is maintained. Thus, we can conclude that anemia is a correctable pathologic finding in elderly people. A number of studies have shown a strong relationship between fatigue and anemia, but few studies investigate to what degree age is a factor in weakness and fatigue. In a study of 375 anemic cancer patients with a median age of 61 years, age as a covariate in multiple linear regression analysis failed to reach significance for most measures of function and quality of life (QOL), including measures of energy, activities, mental health, general cancer-related QOL, and overall QOL. Additional analysis suggests that other factors, including cancer progression, hemoglobin change, and baseline hemoglobin levels, are much more important in determining change in functional and quality-of-life scores. In another set of 2,000 cancer patients and 1,000 controls, cancer patients experienced significantly more fatigue compared with controls. There was no correlation between cancer patient age and fatigue, while in controls the cohort aged 65 or more reported more fatigue than did younger subjects. Finally, measurement of QOL in the general population demonstrated, for both the Short-Form 36 and Functional Assessment of Cancer Therapy - Anemia questionnaires, that age alone is not significantly correlated with QOL. We suggest that chronic conditions such as fatigue and anemia are no more "normal" in an aging population than in a general population, and that all patients with chronic conditions be adequately treated and counseled for their condition. Copyright 2002, Elsevier Science (USA). All rights reserved.