title: Vitamin K intake and mortality in people with chronic kidney disease from NHANES III.
abstract: OBJECTIVE
  Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD), partly due to increased vascular calcification. Vitamin K plays a role in preventing vascular calcification in CKD yet the relationship between vitamin K intake and mortality in CKD patients remains unclear.
  
  
  METHODS
  This observational cohort study included 3401 participants with CKD from the Third National Health and Nutrition Examination Survey. Vitamin K intake was estimated from 24-h dietary recalls (1988-94). Mortality was determined from the National Death Index records through 2006. Cox-proportional hazards regression was used to estimate Hazard Ratios (HR) by comparing those with adequate intake of vitamin K to those with low intake, adjusting for advanced CKD covariates. For sensitivity analysis, these associations were also examined among those with different renal status.
  
  
  RESULTS
  During a median follow-up of 13.3 years (37,408 person-years), 1815 and 876 participants died from all-cause and CVD causes, respectively. 72% of the participants had vitamin K intake lower than the recommended adequate intake. Participants with vitamin K intake higher than recommended adequate intake for vitamin K were associated with lower risk of all-cause (HR = 0.85; 95%: 0.72-1; P = 0.047) and CVD mortality (HR = 0.78; 95%: 0.64-95; P = 0.016). Sensitivity analyses in subgroups with advanced CKD revealed similar findings.
  
  
  CONCLUSIONS
  This observational study suggests that adequate intake of vitamin K may be associated with reduced all-cause and CVD mortality in CKD patients. However, vitamin K may be a marker of a healthy diet; therefore clinical trials may help in clarifying the effect of vitamin K independent of a healthy diet.
authors.affiliation: Department of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China; Centre for Genomic Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China; Department of Pharmacology and Pharmacy, The University of Hong Kong, Pokfulam, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Pokfulam, Hong Kong, China. Electronic address: lung1212@hku.hk.
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Cheung
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, 1200 Centre St., Boston, MA 02131, USA; Harvard Medical School, Boston, MA, USA.
authors.forename: Shivani
authors.initials: S
authors.lastname: Sahni
authors.affiliation: Department of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China; Centre for Genomic Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Bernard M Y
authors.initials: BM
authors.lastname: Cheung
authors.affiliation: Department of Pharmacology and Pharmacy, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Chor-Wing
authors.initials: CW
authors.lastname: Sing
authors.affiliation: Department of Pharmacology and Pharmacy, The University of Hong Kong, Pokfulam, Hong Kong, China; Centre for Safe Medication Practice and Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China. Electronic address: wongick@hku.hk.
authors.forename: Ian C K
authors.initials: IC
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000933:Antifibrinolytic Agents / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000097:blood / Q000188:drug therapy* / Q000209:etiology / Q000401:mortality*; D015331:Cohort Studies; D003625:Data Collection / Q000379:methods; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019370:Observation; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications* / Q000401:mortality; D014812:Vitamin K / Q000008:administration & dosage* / Q000097:blood* / Q000627:therapeutic use*; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use
chemical_list: D000933:Antifibrinolytic Agents; D014815:Vitamins; D014812:Vitamin K
keywords: Cardiovascular disease; Chronic kidney disease; Mortality; Vitamin K; Warfarin