title: Low serum concentrations of alpha-tocopherol are associated with increased risk of hip fracture. A NOREPOS study.
abstract: We investigated the risk of hip fracture according to circulating alpha-tocopherol, a plant-derived substance with antioxidant properties, in community-dwelling older Norwegians. We found a linear increasing risk of hip fracture with lower serum alpha-tocopherol concentrations, with a 51% higher risk in the lowest compared to the highest quartile.
  
  
  BACKGROUND
  Oxidative stress is a suggested contributing cause of osteoporosis and fractures. Vitamin E (α-tocopherol) has potent antioxidant properties in humans. The relationship between circulating α-tocopherol and fracture risk is not established. The aim of this study was to investigate the association between serum α-tocopherol concentrations and risk of hip fracture during up to 11 years of follow-up.
  
  
  METHODS
  We performed a case-cohort analysis among 21,774 men and women aged 65-79 years who participated in four community-based health studies in Norway 1994-2001. Serum α-tocopherol concentrations at baseline were determined in 1,168 men and women who subsequently suffered hip fractures (median follow-up 8.2 years) and in a random sample (n = 1,434) from the same cohort. Cox proportional hazard regression adapted for gender-stratified case-cohort data was performed.
  
  
  RESULTS
  Median (25, 75 percentile) serum α-tocopherol was 30.0 (22.6, 38.3) μmol/L, and it showed a linear inverse association with hip fracture: hazard ratio (HR) 1.11 (95% confidence interval (CI) 1.04-1.20) per 10-μmol/L decrease in serum α-tocopherol, adjusted for gender and study center. The lowest compared to the highest quartile conferred an HR of 1.51 (95% CI 1.17-1.95), adjusted for gender and study center. Adjustment for smoking, month of blood sample, BMI, education, physical inactivity, self-rated health, and serum 25-hydroxyvitamin D (25(OH)D) yielded similar results. Taking serum total cholesterol concentration into account attenuated the association somewhat: HR of hip fracture was 1.37 (95% CI 1.05-1.77) in first versus fourth quartile of serum α-tocopherol/total cholesterol ratio.
  
  
  CONCLUSIONS
  Low serum concentrations of α-tocopherol were associated with increased risk of hip fracture in older Norwegians.
authors: Division of Epidemiology, Norwegian Institute of Public Health, P.O. Box 4404, Nydalen, 0403, Oslo, Norway, kristin.holvik@fhi.no.
authors: K
authors: K
authors: Holvik
authors: C G
authors: CG
authors: Gjesdal
authors: G S
authors: GS
authors: Tell
authors: G
authors: G
authors: Grimnes
authors: B
authors: B
authors: Schei
authors: E M
authors: EM
authors: Apalset
authors: S O
authors: SO
authors: Samuelsen
authors: R
authors: R
authors: Blomhoff
authors: K
authors: K
authors: Michaëlsson
authors: H E
authors: HE
authors: Meyer
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002784:Cholesterol / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D009664:Norway / Q000453:epidemiology; D058866:Osteoporotic Fractures / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D014811:Vitamin E Deficiency / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D024502:alpha-Tocopherol / Q000097:blood*
chemical_list: D015415:Biomarkers; D002784:Cholesterol; D024502:alpha-Tocopherol