Serum cobalamin and methylmalonic acid in Alzheimer dementia

Acta Neurol Scand. 1993 Jun;87(6):475-81. doi: 10.1111/j.1600-0404.1993.tb04140.x.

Abstract

The cobalamin status was evaluated in Alzheimer dementia (n = 26), other dementias (n = 24), various gerontopsychiatric disorders (n = 25), and in neuro-psychiatrically healthy controls (n = 20). Supplementing serum cobalamin we measured methylmalonic acid (MMA), a metabolite accumulating early in cobalamin deficiency. Subnormal cobalamin and/or clearly elevated MMA concentrations were found in 11 cases: 7 Alzheimer patients (27%), 2 with other dementias (8%), one psychiatric patient (4%), and one control (5%). None presented the typical neurologic features of cobalamin deficiency and macrocytosis was found in only one. The mean cobalamin concentration was significantly lower in Alzheimer patients (179 +/- 18 pmol/l) than in the age-matched controls (256 +/- 23 pmol/l) (p = 0.013) and the other patient groups. Correspondingly, the mean MMA level was higher in the Alzheimer group (0.480 +/- 0.062 mumol/l) than in any other diagnostic group (controls: 0.347 +/- 0.040 mumol/l). Comparing the Alzheimer group to the other groups as a whole, the elevation was significant (p = 0.0097). Our findings indicate that Alzheimer patients are particularly prone to cobalamin deficiency, and even subtle biochemical signs of deficiency seem to justify treatment.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / blood*
  • Alzheimer Disease / diagnosis
  • Dementia / blood*
  • Dementia / diagnosis
  • Diagnosis, Differential
  • Erythrocyte Indices
  • Erythrocytes / metabolism
  • Female
  • Folic Acid / blood
  • Humans
  • Male
  • Mental Disorders / blood
  • Mental Disorders / diagnosis
  • Methylmalonic Acid / blood*
  • Middle Aged
  • Reference Values
  • Risk Factors
  • Vitamin B 12 / blood*
  • Vitamin B 12 Deficiency / blood
  • Vitamin B 12 Deficiency / diagnosis

Substances

  • Methylmalonic Acid
  • Folic Acid
  • Vitamin B 12