title: Intake of vitamin K1 and K2 and risk of hip fractures: The Hordaland Health Study.
abstract: BACKGROUND
  Evidence of the effect of vitamin K on bone health is conflicting. The aim was to investigate the association between intake of vitamins K1 and K2 and subsequent risk of hip fracture in a general population sample, as well as potential effect modification by apolipoprotein E gene (APOE) status by presence of the E4 allele.
  
  
  METHODS
  1238 men and 1569 women 71-75 years of age were included in the community-based Hordaland Health Study 1997-1999 in Western Norway. Information on hip fracture was obtained from hospitalizations in the region from enrolment until 31 December 2009. Information on intake of vitamins K1 and K2 collected at baseline was used as potential predictors of hip fracture in Cox proportional hazards regression analyses.
  
  
  RESULTS
  Participants in the lowest compared to the highest quartile of vitamin K1 intake had increased risk of suffering a hip fracture (hazard ratio (HR)=1.57 [95% CI 1.09, 2.26]). Vitamin K2 intake was not associated with hip fracture. Presence of APOE4-allele did not increase the risk of hip fracture, nor was there any effect modification with vitamin K1 in relation to risk of hip fracture.
  
  
  CONCLUSIONS
  A low intake of vitamin K1, but not K2, was associated with an increased risk of hip fractures.
authors.affiliation: Department of Public Health and Primary Health Care, University of Bergen, Kalfarveien 31, N-5018 Bergen, Norway. ellen.apalset@isf.uib.no
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Apalset
authors.forename: Clara G
authors.initials: CG
authors.lastname: Gjesdal
authors.forename: Geir E
authors.initials: GE
authors.lastname: Eide
authors.forename: Grethe S
authors.initials: GS
authors.lastname: Tell
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D053327:Apolipoprotein E4 / Q000235:genetics; D015519:Bone Density; D005260:Female; D020022:Genetic Predisposition to Disease; D006620:Hip Fractures / Q000209:etiology* / Q000235:genetics; D006801:Humans; D009664:Norway; D016016:Proportional Hazards Models; D010837:Vitamin K 1 / Q000008:administration & dosage* / Q000009:adverse effects; D024482:Vitamin K 2 / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D053327:Apolipoprotein E4; D024482:Vitamin K 2; D010837:Vitamin K 1