PREVALENCE OF COBALAMIN DEFICIENCY IN THE FRAMINGHAM ELDERLY POPULATION

To determine whether the increased prevalence of low serum cobalamin c oncentrations in elderly people represents true deficiency, serum conc entrations of cobalamin and folate and of metabolites that are sensiti ve indicators of cobalamin deficiency were measured in 548 surviving m embers of the original Framingham Study cohort. Serum cobalamin concen trations < 258 pmol/L were found in 222 subjects (40.5%) compared with 17.9% of younger control subjects (P < 0.001). Serum methylmalonic ac id and total homocysteine concentrations were markedly elevated in ass ociation with cobalamin values < 258 pmol/L in 11.3% and 5.7%, respect ively, of the cohort. Both metabolites were increased in 3.8% of the c ohort, associated with significantly lower erythrocyte counts and high er mean cell volumes. Serum metabolites correlated best with serum cob alamin values, even when subnormal determinations were excluded. The p revalence of cobalamin deficiency was greater than or equal to 12% in a large sample of free-living elderly Americans. Many elderly people w ith ''normal'' serum vitamin concentrations are metabolically deficien t in cobalamin or folate.