[Selenium deficiency-associated macrocytic anemia in elderly patients receiving parenteral nutrition]

Limited data exist on the prevalence and treatment of macrocytic anemia associated with selenium deficiency. We analyzed data from 21 patients receiving parenteral nutrition (PN). Twelve patients (57%) showed macrocytic anemia, and all 12 had serum selenium levels below the detection limit. Selenium supplementation therapy (sodium selenite, 100 µg/day for 10 days) was administered to a total of 14 patients (aged 79-103 years, PN duration 10-55 months), comprising these 12 patients and two additional anemic patients who presented with marked macrocytosis. After supplementation, serum selenium levels increased transiently but remained below the reference range. Mean corpuscular volume (MCV) showed a transient decline after selenium supplementation, followed by a gradual recovery. The nadir of MCV occurred 10.8 months after supplementation, after which MCV began to increase, indicating a U-shaped trajectory over time. No significant change was observed in hemoglobin levels. Macrocytic changes observed during PN were common manifestations of selenium deficiency and improved with short-term selenium supplementation.