Anemia and aging: an overview of clinical, diagnostic and biological issues

Anemia, usually mild, is one of the more common problems of the aged, especially in men. Although the anemia is often multifactorial, the specific entities can be grouped into three broad categories: (a) anemias due to causes more common in the elderly; (b) anemias without special predilection for the elderly; (c) anemias of unknown cause. The major biological questions concern the third category, which accounts for 14-17% of the anemias, and whether senescence itself contributes to anemia. Current opinion favors a diminished erythropoietic reserve with aging, but the data are inconsistent and the mechanism has not been established. It may be that cytokine modulation of erythropoiesis is abnormal. Some findings in unexplained anemia bear partial resemblance to the changes of anemia of chronic disease, suggesting the possibility that subtle unidentified inflammatory responses of unknown origin may be operative in many elderly people. Of the anemias of known cause that are especially common in the elderly, anemia of chronic disease is an important entity but is sometimes obscured or overlooked and its diagnosis rests on crude tests. Cobalamin deficiency is very common also, although most cases are mild and not accompanied by anemia. Because the basic diagnostic approach to anemia is neither complex nor very invasive and anemia may be a marker of poor prognosis, attribution of anemia to senescence is not advisable until other causes have been ruled out.