Anemia caused by vitamin B12 deficiency in elderly subjects over 75 years of age: new hypotheses and a study of 20 cases.

Purpose, - New hypotheses have recently been developed on vitamin B12 defic iency and the frequently observed occurrence in the elderly subject of food cobalamin malabsorption, i.e., the non-dissociation of B12 and its carrier protein (ND B12), and the possibility of rectifying this imbalance by oral crystalline B12 supplementation. The aim of this study was therefore to co nfirm these hypotheses in a series of patients aged over 75 years with anem ia due to B12 deficiency. Methods. -A retrospective study was carried out over a 5-year period on pat ients aged over 75 years presenting with megaloblastic anemia (hemoglobin [ Hb] < 12 g/dL) and vitamin B12/cobalamin deficiency (B12 < 160 pg/mL). Results.- Twenty cases were analyzed. The average age of the patient popula tion was 82.5 +/- 6 years, and the F/M sex ratio was 1:2. Mean Hb levels we re 7.9 +/- 2.4 g/dL, mean serum B12 levels were 83 +/- 24 pg/mL, and mean h omocysteinemic levels were 35 +/- 27 mu mol/L. The diagnosis was as follows : food cobalamin malabsorption/ND B12 (n = 10), Biermer's disease/perniciou s anemia (n = 5), malabsorption due to pancreatic insufficiency (n = Il, an d low dietary B12 levels (n = I). Disorders associated with ND B12 were: at rophic gastritis and Helicobacter pylori infection (n = 6), antacid or bigu anide intake (n = 3), alcohol abuse (n = 2), or idiopathic syndrome (n = 2) . In the patients who were followed up (n = 10), i.m. (n = 5) or oral (n = 5) administration of crystalline B12 resulted in the correction of hematolo gical abnormalities. Conclusion. - In the elderly subject, food cobalamin/ND B12 malabsorption a ppears to be the main cause of B12 deficiency, and is frequently associated with atrophic gastritis. In these cases, administration of oral crystallin e B12 may be an efficient means of treating this disorder, (C) 2000 Edition s scientifiques et medicales Elsevier SAS.