title: [Population reference ranges and determinants of plasma homocysteine levels].
abstract: BACKGROUND
  There is a well-known relationship between plasma homocysteine levels and the risk of cardiovascular events. Determination of homocysteine levels may also be of potential diagnostic aid in several clinical situations. The construction of reference ranges should take age and sex variations into account.
  
  
  METHODS
  396 healthy subjects were recruited (172 males and 224 females). Fasting plasma homocysteine levels were measured using the fluorescein polarization immunoassay technique (FPIA). Plasma levels of creatinine, folates, vitamin B12 and TSH were measured. 90% reference ranges were estimated by fractional polynomial regression methods.
  
  
  RESULTS
  Homocysteine plasma levels ranged from 4.35 micromol/l to 17,71 micromol/l (median 8.62 micromol/l). These concentrations increased with age and were higher in males (median 9.53 micromol/l [range: 5.45-17.5]) than in females (median 7.79 micromol/l[range: 4.35-17.71]). Sex differences decreased in the elderly. Creatinine plasma levels (with a positive association) and folate levels (with a negative association) had a statistically significant effect on the specific distribution of homocysteine levels according to age and sex.
  
  
  CONCLUSIONS
  Age-and sex-specific reference ranges of plasma homocysteine have been defined. Renal function along with folate plasma levels have to be accounted for when assessing these distribution ranges.
authors.affiliation: Unidad de Epidemiología Clínica, Hospital de Cruces, Barakaldo, Vizcaya, Spain. jipijoan@heru.osakidetza.net
authors.forename: J I
authors.initials: JI
authors.lastname: Pijoán Zubizarreta
authors.forename: I
authors.initials: I
authors.lastname: Irigoien Garbizu
authors.forename: C
authors.initials: C
authors.lastname: Aguirre Errasti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values
chemical_list: D006710:Homocysteine