Low serum levels of 25-hydroxyvitamin D predict hip fracture in the elderly.
A NOREPOS study.
J Clin Endocrinol Metab. 2013 May 15.
Holvik K, Ahmed LA, Forsmo S, Gjesdal CG, Grimnes G, Samuelsen SO, Schei B, Blomhoff R, Tell GS, Meyer HE.
Department of Public Health and Primary Health Care, University of Bergen, Norway.
Background:Despite considerable interest, the relationship between circulating 25-hydroxyvitamin D and risk of hip fracture is not fully established.
Objective:To study the association between serum 25-hydroxyvitamin D concentrations (s-25(OH)D) and risk of hip fracture in Norway, a high-latitude country that has among the highest hip fracture rates worldwide.
Methods:N=21,774 men and women aged 65-79 attended four community-based health studies during 1994-2001. Information on subsequent hip fractures were retrieved from electronic hospital discharge registers, with maximum follow-up 10.7 years. Using a stratified case-cohort design, s-25(OH)D was determined by HPLC-APCI-MS in stored serum samples in hip fracture cases (n=1175; 307 men, 868 women) and in gender-stratified random samples (n=1438). Cox proportional hazards regression adapted for the case-cohort design was performed.
Results: We observed an inverse association between s-25(OH)D and hip fracture; those with s-25(OH)D in the lowest quartile (<42.2 nmol/l) had a 38% (95% CI 9-74%) increased risk of hip fracture compared with the highest quartile (>=67.9 nmol/l) in a model accounting for age, gender, study center, and BMI. The association was stronger in men than in women: HR 1.65 (95% CI 1.04-2.61) versus HR 1.25 (95% CI 0.95-1.65).
Conclusion: In this prospective case-cohort study of hip fractures, the largest ever reported, we found an increased risk of hip fracture in subjects in the lowest compared to the highest quartile of serum 25-hydroxyvitamin D. In accordance with findings of previous community-based studies, low vitamin D status was a modest risk factor for hip fracture.
PMID: 23678033