The Significance of Subnormal Serum Vitamin B ₁₂ Concentration in Older People: A Case Control Study

Abstract

Almost 90% of older patients with serum B12 < 150 pmol/L show evidence of tissue vitamin B12 deficiency. Deficiency becomes manifest in older patients at relatively higher concentrations of serum B12 than in younger subjects, possibly because of lower levels of holotranscobalamin II in the older patients.