title: Plasma homocysteine, folate, and vitamin B 12 and the risk of hip fracture: the hordaland homocysteine study.
abstract: Homocysteine and related factors were evaluated as risk factors for subsequent hip fractures among 4766 elderly men and women. High levels of homocysteine and low levels of folate predicted fracture, whereas vitamin B12 and genotypes were not related to fracture risk. High homocysteine may be a modifiable risk factor for hip fracture.
  
  
  BACKGROUND
  Elevated plasma total homocysteine (tHcy) and deficiencies of folate and vitamin B12 are associated with risk of osteoporosis and fracture. We examined whether plasma levels of tHcy, folate, and vitamin B12 and the methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298C-->T polymorphisms predicted hip fracture.
  
  
  METHODS
  This was a population-based prospective study of 2639 women and 2127 men who were 65-67 yr at enrollment in 1992-1993. Information on hip fracture was obtained from computerized records of discharge diagnoses from all hospitalizations in the region in the period between enrollment and November 30, 2005. Cox proportional hazard regression was used to estimate fracture risk according to levels of plasma tHcy, folate, and vitamin B12 and for different genotypes.
  
  
  RESULTS
  Over a median follow-up period of 12.6 yr, hip fracture was recorded in 184 (7.0%) women and 90 (4.2%) men. The adjusted hazard ratio (95% CI) for fracture in subjects with high (>or=15 microM) compared with low levels (<9.0 microM) of tHcy was 2.42 (1.43-4.09) among women and 1.37 (0.63-2.98) among men. Dose-response analyses indicated a positive association between plasma tHcy and risk of fracture in both sexes and a negative association between plasma folate and risk of fracture among women only. Plasma vitamin B12 level or MTHFR genotype was not significantly related to risk of fracture after adjustments for confounding factors. The association between tHcy and risk of hip fracture was only slightly weakened by adjustments for plasma levels of vitamin B12 and folate.
  
  
  CONCLUSIONS
  tHcy seems to be a predictor for hip fracture among elderly men and women. Folate was a predictor among women only, whereas vitamin B12 and MTHFR genotype did not predict hip fracture. Our data corroborate the hypothesis that homocysteine may play a role in the pathogenesis of osteoporotic fractures.
authors.affiliation: Department of Public Helath and Primary Health Care, University of Bergen, Bergen, Norway. clara.gjesdal@isf.uib.no
authors.forename: Clara Gram
authors.initials: CG
authors.lastname: Gjesdal
authors.forename: Stein Emil
authors.initials: SE
authors.lastname: Vollset
authors.forename: Per Magne
authors.initials: PM
authors.lastname: Ueland
authors.forename: Helga
authors.initials: H
authors.lastname: Refsum
authors.forename: Haakon E
authors.initials: HE
authors.lastname: Meyer
authors.forename: Grethe S
authors.initials: GS
authors.lastname: Tell
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D005492:Folic Acid / Q000097:blood*; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000097:blood* / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000097:blood / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D015415:Biomarkers; D006710:Homocysteine; D005492:Folic Acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; D014805:Vitamin B 12