title: [Serum vitamin B12 levels in an adolescent population in Madrid].
abstract: BACKGROUND
  Serum vitamin B12 concentration levels in children are essential to establish values in order to compare different regions or countries, and for considering e the possibility of supplementing diets with group B vitamins as a secondary prevention against cardiovascular diseases.
  
  
  METHODS
  A cross-sectional epidemiological study was carried out to asses serum vitamin B12 levels in school children, 13-15 years of age, in Madrid. Folate and vitamin B12 vitamin determinations were performed on fasting blood samples. Genotype C677T of methylentetrahydrofolate reductase (MTHFR) enzyme was determined by PCR.
  
  
  RESULTS
  The mean vitamin B12 level obtained in our study was 503 pmol/l; CI 95 % CI (478-528 pmol/l). The median was 471 pmol/l; interquartile range (IR) (337-632 pmol/l). No statistically significant differences were found by age or C677T genotype for MTHFR. Serum vitamin B12 concentrations were significantly higher in females. Prevalence of vitamin B12 deficiency (< 224 pmol/l) was 6 % in males and 4 % in females.
  
  
  CONCLUSIONS
  Reference values for serum vitamin B12 concentrations in an adolescent population are presented. Prevalence of vitamin B12 deficiencies is higher in males.
authors.affiliation: Area de Medicina Preventiva y Salud Pública, Departamento de Ciencias de la Salud, Universidad Rey Juan Carlos, Alcorcón, España. ruth.gil@urjc.es
authors.forename: R
authors.initials: R
authors.lastname: Gil Prieto
authors.forename: J
authors.initials: J
authors.lastname: Esteban Hernández
authors.forename: V
authors.initials: V
authors.lastname: Hernández Barrera
authors.forename: B
authors.initials: B
authors.lastname: Cano
authors.forename: M
authors.initials: M
authors.lastname: de Oya
authors.forename: A
authors.initials: A
authors.lastname: Gil de Miguel
mesh_terms: D000293:Adolescent; D002391:Catchment Area, Health; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000453:epidemiology* / Q000235:genetics
chemical_list: D042965:Methylenetetrahydrofolate Reductase (NADPH2)