Approximately 15% of people aged more than 60 years old have a cobalamin (vitamin B12) deficiency, mainly in relation with food-cobalamin malabsorption (FCM). To date, no study has documented this disorder in the elderly. There is also little information on clinical consequences.

We studied 92 elderly patients with well-established FCM who were extracted from an observational cohort study (1995-2004) of 172 consecutive elderly patients with documented cobalamin deficiency.

The median patient age was 76 ± 8 years; 60 patients were women. The most common clinical manifestations were neurologic or psychologic: mild sensory polyneuropathy (44.6%), confusion or impaired mental functioning (22.8%), and physical asthenia (20.7%). Hematologic abnormalities were reported in at least one third of the patients: anemia (21%), leukopenia (10.9%), thrombopenia (8.7%), and pancytopenia (6.5%). All patients had low serum vitamin B12 levels (<200 pg/mL), with a mean value (± standard deviation) of 131 ± 38 pg/mL and total serum homocysteine level of 22.1 ± 9.3 μmol/L. The mean hemoglobin level was 10.9 ± 2.5 g/dL and the mean erythrocyte cell volume 95.7 ± 12.7 fL. Correction of the serum vitamin B12 levels and hematologic abnormalities was achieved equally well in patients treated with either intramuscular or oral crystalline cyanocobalamin.

This study suggests that in elderly patients, FCM may be associated with significant neurologic, psychologic, and hematologic abnormalities, which seem to respond equally well to either oral or parenteral vitamin B12 therapy.