title: Vitamin B12 deficiency in the aged: a population-based study.
abstract: BACKGROUND
  vitamin B12 deficiency is common in the aged, but it is controversial whether only some risk groups should be investigated instead of screening the entire aged population.
  
  
  OBJECTIVE
  to describe the prevalence of vitamin B12 deficiency in the Finnish aged, and to find out if the subjects especially prone to vitamin B12 deficiency could be identified by the risk factors or clinical correlates.
  
  
  METHODS
  a cross-sectional, population-based study of 1048 aged subjects (age 65-100 years) was carried out. Data on lifestyle factors and clinical conditions were collected, physical examinations were conducted and laboratory variables related to vitamin B12 were measured.
  
  
  RESULTS
  vitamin B12 deficiency had been previously diagnosed in 27 (2.6%) subjects, and a laboratory diagnosis (total vitamin B12 <150 pmol/l, or total vitamin B12 150-250 pmol/l and holotranscobalamin < or =37 pmol/l and homocysteine > or =15 micromol/l) was made for 97 (9.5%) subjects. Low serum total vitamin B12 (<150 pmol/l) was observed in 6.1% and borderline total vitamin B12 (150-250 pmol/l) in 32% of the subjects. Male gender (OR 1.9, 95% CI 1.2-2.9), age > or =75 (OR 2.2, 95% CI 1.4-3.4) and refraining from milk products (OR 2.3, 95% CI 1.2-4.4) increased the probability for vitamin B12 deficiency. Anaemia (OR 1.3, 95% CI 0.7-2.3) or macrocytosis (OR 1.2, 95% CI 0.6-2.7) did not predict vitamin B12 deficiency.
  
  
  CONCLUSIONS
  undiagnosed vitamin B12 deficiency is remarkably common in the aged, but no specific risk group for screening can be identified. Thus, biochemical screening of unselected aged population is justified. General practitioners play a key role in diagnosing early vitamin B12 deficiency.
authors.affiliation: Department of Clinical Chemistry, University of Turku, Turku, Finland. sailalo@utu.fi
authors.forename: Saila
authors.initials: S
authors.lastname: Loikas
authors.forename: Pertti
authors.initials: P
authors.lastname: Koskinen
authors.forename: Kerttu
authors.initials: K
authors.lastname: Irjala
authors.forename: Minna
authors.initials: M
authors.lastname: Löppönen
authors.forename: Raimo
authors.initials: R
authors.lastname: Isoaho
authors.forename: Sirkka-Liisa
authors.initials: SL
authors.lastname: Kivelä
authors.forename: Tarja-Terttu
authors.initials: TT
authors.lastname: Pelliniemi
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D008019:Life Style; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology