Low serum concentrations of vitamin E are associated with increased risk of hip fracture in older Norwegians. A NOREPOS study

Aim: We aimed to study the association between α-tocopherol concentrations in serum and risk of hip fractures in older men and women. Methods: In the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS) we performed a case-cohort analysis in 21,774 men and women aged 65-79 years (mean 72 y) who underwent baseline examinations in four community-based health studies during 1994-2001. Data on incident hip fractures were retrieved from electronic patient administrative systems. Frozen serum samples from baseline were analyzed in participants who suffered a hip fracture during median 8.2 years of follow-up (n=1168) and in sex-stratified random samples from baseline (n=1434). α-tocopherol was determined by high pressure liquid chromatography (HPLC)-fluorescence detection. Cox proportional hazards regression adapted for the case-cohort design was performed with adjustment for age, sex, and study center. Results: We observed a linear inverse relation between serum α-tocopherol levels and hip fracture, with hazard ratio (HR) 1.11 (95% CI 1.04-1.20) per 10 µmol/l lower serum α-tocopherol. HR of hip fracture in the lowest (=38.3 µmol/l) quartile of serum α-tocopherol was 1.51 (95% CI 1.17-1.95). Adjustment for serum concentrations of 25(OH)D and retinol, smoking, month of blood sample, body mass index, education, physical inactivity and self-rated health yielded similar results. Conclusion: Low serum concentrations of α-tocopherol were associated with increased risk of hip fracture in older Norwegian men and women.