title: [Gender differences in serum homocysteine levels and associated factors].
abstract: BACKGROUND
  Homocysteine (Hcy) is an important independent risk factor for vascular diseases. Its level is determined by genetic polymorphism of several enzymes in association with nutritional factors. Higher Hcy levels were found in men than in women, however the clinical significance of this phenomenon remains to be elucidated. The aim of this study was to analyze the gender differences in Hcy levels in relation to associated factors and to assess in which range of Hcy these differences are mainly expressed.
  
  
  RESULTS
  The series comprised of 257 males and 239 females, mean age 52.9 and 52.3 years, resp., selected from the population study Pils II. All subjects were examined by a standard protocol, to assess clinical, anthropometrical and laboratory variables. Hcy and methionine levels were estimated by ion exchange chromatography, other laboratories using standard kits. The methods were validated by a reference laboratory. Statistical analyses were done by Wilcoxon's unpaired test and multiple linear regression. We found in males significantly higher Hcy levels (13.1 vs. 11.5 mumol/l, p < 0.0001) than in females. This difference persisted only in the range of normal Hcy levels (11.1, 10.2 mumol/l, p < 0.0001), i.e. up to 15 mumol/l (1st-4th quintile of the Hcy distribution) and not in the top quintile, considered as mild hyperhomocysteinaemia. We found in males, with normal Hcy levels, significantly higher serum methionine (23.8 vs. 22.4 mumol/l, p < 0.0001), creatinine (91.5 vs 80.9 mumol/l, p < 0.0001) and a lower methionine/creatinine ratio (0.25 vs. 0.27, p < 0.01). Plasma folates and B12 vitamin in males were also lower than in females, however these differences were only of a borderline statistical significance. On the other hand, in subjects with MHHcy (5th quintile) no gender differences were observed, except in creatinine.
  
  
  CONCLUSIONS
  Higher Hcy levels in males cannot be explained by differences in folate and B12 levels only. We considered also other factors, namely higher demethylation of methionine associated with higher creatinine production in males, which may be influenced by sex hormons.
authors.affiliation: Centrum preventivní medicíny LF UK, II. interní klinika, Plzen.
authors.forename: O
authors.initials: O
authors.lastname: Mayer
authors.forename: J
authors.initials: J
authors.lastname: Simon
authors.forename: H
authors.initials: H
authors.lastname: Rosolová
mesh_terms: D003404:Creatinine / Q000097:blood; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008715:Methionine / Q000097:blood; D008875:Middle Aged; D012727:Sex Characteristics; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D008715:Methionine; D003404:Creatinine; D014805:Vitamin B 12