title: Vitamin B-12 deficiency in the elderly: current dilemmas.
abstract: Vitamin B-12 deficiency is present in up to 15% of the elderly population as documented by elevated methylmalonic acid with or without elevated total homocysteine concentrations in combination with low or low-normal vitamin B-12 concentrations. Clinical signs and symptoms of vitamin B-12 deficiency are insensitive in elderly subjects and comorbidity in these subjects makes responses to therapy difficult to interpret. Many elderly subjects with hyperhomocysteinemia have undiagnosed vitamin B-12 deficiency with elevated serum methylmalonic acid concentrations. Therefore, such elderly subjects should not receive folic acid supplementation before their vitamin B-12 status is diagnosed. Oral vitamin B-12 supplementation may be effective in lowering serum methylmalonic acid values in the elderly. However, the dose of vitamin B-12 in most common multivitamin preparations is too low for this purpose. Research efforts should be directed toward determining practical methods for diagnosing and treating vitamin B-12 deficiency in the millions of elderly subjects with undiagnosed deficiency.
authors.affiliation: Department of Medicine, University of Colorado Health Sciences Center, Denver 80220, USA. jonesjo@jove.UCHSC.edu
authors.forename: S P
authors.initials: SP
authors.lastname: Stabler
authors.forename: J
authors.initials: J
authors.lastname: Lindenbaum
authors.forename: R H
authors.initials: RH
authors.lastname: Allen
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism; D008764:Methylmalonic Acid / Q000097:blood*; D008875:Middle Aged; D014805:Vitamin B 12 / Q000008:administration & dosage; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000188:drug therapy / Q000378:metabolism
chemical_list: D000214:Acyl Coenzyme A; D006710:Homocysteine; C015357:methylmalonyl-coenzyme A; D008764:Methylmalonic Acid; D008715:Methionine; D014805:Vitamin B 12