title: Methylmalonic acid and cognitive function in the Medical Research Council Cognitive Function and Ageing Study.
abstract: BACKGROUND
  An elevated blood concentration of homocysteine is an established risk factor for cognitive impairment and dementia, but associations between cognition and methylmalonic acid (MMA), a related metabolic marker of vitamin B-12 deficiency, are less clear.
  
  
  OBJECTIVE
  The aim was to determine the utility of serum MMA and holotranscobalamin as markers of vitamin B-12 status in relation to cognitive function and to investigate their association with discrete cognitive domains.
  
  
  METHODS
  This was a cross-sectional survey of 84 nondemented elderly participants (aged >69 y) from the Welsh cohort of the Medical Research Council's Cognitive Function and Ageing Study. Cognitive status was determined by Mini-Mental State Examination (MMSE) and the Cognitive Section of the Cambridge Mental Disorders of the Elderly Examination (CAMCOG).
  
  
  RESULTS
  Nearly one-half (43%) of the persons selected had likely metabolically significant vitamin B-12 deficiency. Higher MMA concentrations were associated with lower MMSE scores independent of age and education (P = 0.007). MMA concentration correlated inversely with CAMCOG scores of ideational praxis (P < 0.05) and language comprehension (P < 0.05) and expression (P < 0.01). Serum folate correlated weakly but significantly with language (P < 0.05), remote memory (P < 0.05), and constructional and ideational praxis scores (P < 0.05 and P < 0.01, respectively).
  
  
  CONCLUSIONS
  The high prevalence of likely metabolically significant vitamin B-12 deficiency in the elderly is associated with lower cognitive function scores and particularly with lower scores of language comprehension and expression.
authors.affiliation: University Department of Psychiatry, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Cherie
authors.initials: C
authors.lastname: McCracken
authors.forename: Peter
authors.initials: P
authors.lastname: Hudson
authors.forename: Richard
authors.initials: R
authors.lastname: Ellis
authors.forename: Andrew
authors.initials: A
authors.lastname: McCaddon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood; D005494:Folic Acid Deficiency / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D005853:Geriatrics; D006801:Humans; D007807:Language Tests; D008137:Longitudinal Studies; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000150:complications* / Q000453:epidemiology; D014803:Vitamin B Complex / Q000097:blood*
chemical_list: D014803:Vitamin B Complex; D008764:Methylmalonic Acid; D005492:Folic Acid