This Article  • Full text  • PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on HighWire  • Citing articles on ISI (26)  • Contact me when this article is cited  Related Content  • Related article  • Similar articles in this journal  Social Bookmarking   What's this?

Anne-Mette Hvas, MD; Jørgen Ellegaard, MD; Ebba Nexø, MD

Arch Intern Med. 2001;161:1534-1541.

Background  The prevalence of vitamin B₁₂ deficiency, defined as an elevated concentration of plasma methylmalonic acid (P-MMA), has been estimated to be 15% to 44% in the elderly. However, we do not know whether an increased P-MMA level actually indicates or predicts a clinical condition in need of treatment.

Participants and Methods  In a follow-up study, 432 individuals not treated with vitamin B₁₂ were examined 1.0 to 3.9 years after initial observation of an increased P-MMA concentration (>0.28 µmol/L). The examination included laboratory tests, a structured interview to disclose symptoms, a food frequency questionnaire, and a clinical examination including a Neurological Disability Score.

Results  Variation in P-MMA levels over time was high (coefficient of variation, 34%). In only 16% of participants, P-MMA levels increased substantially, whereas 44% showed a decrease. Level of P-MMA was significantly but not strongly associated with levels of plasma cobalamins (r = -0.22, P<.001) and plasma total homocysteine (r = 0.37, P<.001). After adjustment for age and sex, we found no associations between P-MMA concentration and the total symptom score (P = .61), the total Neurological Disability Score (P = .64), or other clinical manifestations related to vitamin B₁₂ deficiency.

Conclusions  An increased level of P-MMA did not predict a further increase with time and clinical manifestations related to vitamin B₁₂ deficiency. We therefore challenge the use of an increased P-MMA concentration as the only marker for diagnosis of vitamin B₁₂ deficiency.

From the Departments of Hematology, Aarhus Amtssygehus (Drs Hvas and Ellegaard), and Clinical Biochemistry, Aarhus Kommunehospital (Dr Nexø), Aarhus University Hospital, Aarhus, Denmark.

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati     What's this?

RELATED ARTICLE

Archives of Internal Medicine Reader's Choice: Continuing Medical Education
Arch Intern Med. 2001;161(12):1560-1561.
FULL TEXT  

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

How I treat cobalamin (vitamin B12) deficiency
Carmel
Blood 2008;112:2214-2221.
ABSTRACT | FULL TEXT  

Vitamin B12 deficiency in the aged: a population-based study
Loikas et al.
Age Ageing 2007;36:177-183.
ABSTRACT | FULL TEXT  

Significant correlations of plasma homocysteine and serum methylmalonic acid with movement and cognitive performance in elderly subjects but no improvement from short-term vitamin therapy: a placebo-controlled randomized study
Lewerin et al.
Am. J. Clin. Nutr. 2005;81:1155-1162.
ABSTRACT | FULL TEXT  

Cobalamin deficiency in elderly patients
Ray and Cole
CMAJ 2005;172:448-450.
FULL TEXT  

Facts and Recommendations about Total Homocysteine Determinations: An Expert Opinion
Refsum et al.
Clin. Chem. 2004;50:3-32.
ABSTRACT | FULL TEXT  

Holotranscobalamin as an Indicator of Dietary Vitamin B12 Deficiency
Lloyd-Wright et al.
Clin. Chem. 2003;49:2076-2078.
FULL TEXT  

Increased plasma homocysteine levels without signs of vitamin B12 deficiency in patients with multiple sclerosis assessed by blood and cerebrospinal fluid homocysteine and methylmalonic acid
Vrethem et al.
Mult Scler 2003;9:239-245.
ABSTRACT  

Methylmalonic Acid and Clinical Practice
Aguirre et al.
Arch Intern Med 2002;162:102-103.
FULL TEXT