In our study, a small part of the individuals were anemic but, as suggested by the results of a sensitivity analysis, the association between copeptin and markers of erythropoiesis was seen both among individuals classified as having anemia as well as among individuals without anemia, which in turn would indicate that the vasopressin system may be involved in stimulation of erythropoiesis independently of a low erythrocyte count. This evidence concerns the gene AVP and anemia (phenotype).