High prevalence of cobalamin deficiency in the elderly.

In summary, we have shown that there is a high prevalence of Cbl deficiency in the elderly. This observation is based on an increase in the number of low and low normal serum Cbl levels, an increase in elevated serum total homocysteine levels that correct with Cbl therapy, and an increase in elevated serum methylmalonic acid levels that also correct with Cbl therapy. These observations may be of great clinical importance since Cbl deficiency may be a common and treatable cause of vascular disease.