title: Abnormal homocysteine metabolism in rheumatoid arthritis.
abstract: OBJECTIVE
  To assess total homocysteine (tHcy) metabolism in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  Assessments were performed to determine the fasting levels of tHcy and the increase in tHcy in response to methionine (Met) challenge in blood samples from 28 patients with RA and 20 healthy age-matched control subjects.
  
  
  RESULTS
  Fasting levels of tHcy were 33% higher in the RA patients than in the control subjects (mean +/- SD 11.7 +/- 1.5 nmoles/ml versus 8.8 +/- 1.1 nmoles/ml; P < 0.01). Four hours after Met challenge, the increase in plasma tHcy levels (delta tHcy) was higher in the RA patients (20.9 +/- 10.4 nmoles/ml) than in the control subjects (15.5 +/- 1.6 nmoles/ml) (P < 0.02). In a subgroup analysis, the delta tHcy in patients taking methotrexate (12.9 +/- 2.2 nmoles/ml) did not differ from that in the control group, while the delta tHcy in patients not taking methotrexate (25.3 +/- 1.7 nmoles/ml) was significantly higher (P < 0.0001).
  
  
  CONCLUSIONS
  Elevated tHcy levels occur commonly in patients with RA, and may explain some of the increased cardiovascular mortality seen in such patients. Studies of the prevalence and mechanism of hyperhomocysteinemia in RA are warranted.
authors.affiliation: Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
authors.forename: R
authors.initials: R
authors.lastname: Roubenoff
authors.forename: P
authors.initials: P
authors.lastname: Dellaripa
authors.forename: M R
authors.initials: MR
authors.lastname: Nadeau
authors.forename: L W
authors.initials: LW
authors.lastname: Abad
authors.forename: B A
authors.initials: BA
authors.lastname: Muldoon
authors.forename: J
authors.initials: J
authors.lastname: Selhub
authors.forename: I H
authors.initials: IH
authors.lastname: Rosenberg
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000209:etiology / Q000378:metabolism*; D005215:Fasting; D005260:Female; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008297:Male; D008715:Methionine / Q000008:administration & dosage; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D014805:Vitamin B 12 / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000378:metabolism
chemical_list: D006710:Homocysteine; D008715:Methionine; D014805:Vitamin B 12; D008727:Methotrexate