Serum erythropoietin levels in the elderly.

We evaluated the relationship between erythropoietin (EPO) and hemoglobin (Hb) concentrations in 156 normal subjects ranging from 60 to 98 years old. EPO was determined by a radioimmunoassay. The serum EPO concentration in subjects with Hb concentrations greater than 12.0 g/dl (26.9 +/- 15.2 mU/ml), was significantly higher than that in younger controls (15.8 +/- 5.0 mU/ml, p less than 0.001). No sex difference in serum EPO level was detected. In addition, there was an inverse semilogarithmic relationship between EPO and Hb concentrations in subjects with Hb concentrations less than 12.0 g/dl (r = -0.559, p less than 0.001). EPO concentrations in the elderly were lower than those in young subjects with iron deficiency anemia with the same Hb level. Thus, in the elderly, a high EPO concentration may be preventing a decrease in the Hb concentration. However, a decreased EPO response to low Hb concentrations may be a contributing factor in anemia in the elderly.