The neurology of cobalamin deficiency in an elderly population in Israel

To evaluate the neurological status in elderly subjects with cobalamin deficiency (CblD) compared with matched non-deficient subjects before and after cobalamin (Cbl) supplementation.

Participants completed a questionnaire on activities of daily living, level of education, medical history, alcohol, nicotine, caffeine, and medication usage and prior consumption of vitamins. They underwent a detailed programmed neurological evaluation which was repeated after 6-9 months of Cbl therapy.

There were 113 subjects with blood Cbl < or =147 pmol/L, methylmalonic acid > or =0.24 mumol/L, and 212 nondeficient subjects (controls). The mean age of the patients and controls was 79.5 +/- 6.9 and 79.5 +/- 5.9 years, respectively. Fifty patients (44.4 %) and 56 controls (26.4%) were found to have mild sensory neuropathy (SN).When subjects with diabetes mellitus (DM) were excluded, however, only 30 (26.5%) patients and 23 (10.8 %) controls had SN. A history of confusional state was more common among the patients than among the controls (12.4 % and 3.3%, respectively) as was a low mini-mental state examination (MMSE) score (20.2% and 15.2%, respectively). No patient had clinical signs compatible with subacute combined degeneration (SCD). Supplementation of Cbl for 6-9 months did not alter the neurological findings,while the biochemical deficiency was corrected.

Mild SN rather than SCD is the main neurological impairment in elderly people with CblD. Short-term supplementation of CbL can correct the biochemical deficiency without affecting the neurological impairment.