Reduced erythropoietin secretion in senile anemia.

To investigate the etiology of the age-related decrease in hemoglobin (Hb) concentration, we measured serum erythropoietin (EPO), serum iron, total iron binding capacity, and serum ferritin levels in 247 elderly subjects aged 60-99 years. EPO levels were determined by radioimmunoassay. An age-related increase in the serum EPO concentration (r = 0.220; P < 0.01) and a significant inverse relationship between EPO and Hb concentrations were found in normal elderly subjects without anemia (r = -0.302; P < 0.001), but not in 111 younger controls. Serum EPO levels were slightly higher in elderly subjects with pre-anemic iron deficiency than in the normal elderly subjects (P < 0.05). These results suggest that the EPO secretion is accelerated in the elderly even though the Hb remains above 12.0 g/dl, probably as a compensatory mechanism for peripheral tissue hypoxia. An inverse relationship between the EPO and Hb concentrations was found in the elderly subjects with iron deficiency anemia, but not in those with unexplained senile anemia. The changes of EPO levels were also assessed in 20 elderly subjects who had developed anemia when reviewed after 12 months. Serum EPO levels increased in relation to the decrease in Hb concentration in those with iron deficiency anemia, but not in those with unexplained senile anemia. Reduced EPO secretion thus seems to play a role in the progression of unexplained senile anemia, and recombinant human EPO may possibly be effective for treating this type of anemia by mobilizing excess iron.