title: Hyperhomocysteinemia and vitamin B-12 deficiency are more striking in Syrians than in Germans--causes and implications.
abstract: Hyperhomocysteinemia is an accepted risk factor for coronary artery disease, but the determining factors are not fully understood. We investigated hyperhomocysteinemia and vitamin deficiency in Syrian coronary patients and apparently healthy Syrian and German controls. We enrolled 273 Syrian patients with angiographically confirmed stenosis, along with 159 Syrian and 75 German controls. Plasma total homocysteine (HCY), cystathionine, methylmalonic acid (MMA), vitamin B-6, B-12, folate, lipids, apolipoproteins and methylenetetrahydrofolate reductase (C677T-MTHFR) mutation were analysed. There was a very high prevalence of hyperhomocysteinemia (>12 micromol/l) in Syrians (patients 61%, controls 44%, Germans 16%) together with functional vitamin B-12 deficiency diagnosed by elevated MMA (patients 49%, controls 47%, Germans 3%), which was in contrast to the low frequency of decreased serum vitamin B-12 (12% in patients, 7% in Syrian controls). The HCY concentration in German controls was lower than in Syrians, median 8.8 vs. 11.3 micromol/l. The vitamin B-12 deficiency induces folate trapping; higher levels of folate are needed to prevent hyperhomocysteinemia. Germans achieved the HCY level of < or =12 micromol/l at significantly lower folate concentrations > or =4.4 ng/ml, than Syrians with normal MMA (> or =16.7 nmol/l folate) or Syrians with high MMA (> or =23.3 nmol/l folate). Smoking and homozygous state for C677T-MTHFR mutation contributed to hyperhomocysteinemia. We could confirm that the reasons for hyperhomocysteinemia in Syrians were in fact mostly related to a relative folate deficiency, which is due to a vitamin B-12 shortage. Vitamin B-12 deficiency induces folate trapping. Besides lifestyle, other presently unknown factors may contribute to hyperhomocysteinemia and vitamin B-12 deficiency in Syrians.
authors.affiliation: Department of Clinical Chemistry, Saarland Medical School, Building 40, Kirrberger Str., D-66421 Homburg, Germany. kchwher@uniklinik-saarland.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Herrmann
authors.forename: Rima
authors.initials: R
authors.lastname: Obeid
authors.forename: Muhidien
authors.initials: M
authors.lastname: Jouma
mesh_terms: D000328:Adult; D018912:Arabs; D008078:Cholesterol, LDL / Q000097:blood*; D003327:Coronary Disease / Q000097:blood / Q000208:ethnology*; D005260:Female; D005858:Germany; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000208:ethnology*; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood*; D008875:Middle Aged; D015995:Prevalence; D013593:Syria; D014808:Vitamin D Deficiency / Q000097:blood / Q000208:ethnology*
chemical_list: D008078:Cholesterol, LDL; D006710:Homocysteine; D008764:Methylmalonic Acid