title: The Association of Vitamin D With Femoral Neck Strength: An Additional Evidence of Vitamin D on Bone Health.
abstract: BACKGROUND
  Although bone mineral density (BMD) is a strong predictor of fracture risk, additional parameters, such as bone strength, are needed to predict future fracture risk because of the low sensitivity of BMD for predicting fracture risk.
  
  
  OBJECTIVE
  The objective was to study the association of vitamin D with femoral neck (FN) strength.
  
  
  METHODS
  This was a population-based, cross-sectional study from Korea National Health and Nutrition Examination Surveys.
  
  
  METHODS
  A total of 1209 Koreans (586 men and 623 women) aged ≥50 years participated.
  
  
  METHODS
  We calculated composite indices of FN strength, such as the compression strength index, bending strength index (BSI), and impact strength index, by combining BMD, body weight, and height with the femoral axis length and width, which were measured by dual-energy x-ray absorptiometry.
  
  
  RESULTS
  Multiple regression analysis demonstrated that serum 25-hydroxyvitamin D [25(OH)D] levels were associated with compression strength index, BSI, and impact strength index in both genders. When women were categorized into four quartiles of 25(OH)D, FN BMD and composite indices (except for BSI) significantly increased from the lowest (Q1) to the highest quartile (Q4) (P for trend = .001-.004). In contrast, there is no significant association of quartiles with composite indices in men. When women were divided into two groups according to their serum 25(OH)D levels, the composite indices as well as the FN BMD were markedly higher in subjects with higher 25(OH)D levels (≥51.5 nmol/L).
  
  
  CONCLUSIONS
  These findings provide the first clinical evidence that high serum 25(OH)D levels exhibit higher composite indices of FN strength in a dose-dependent manner, especially in women.
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Hyeonmok
authors.initials: H
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Seung Hun
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: JinJu
authors.initials: J
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Kyeong-Hye
authors.initials: KH
authors.lastname: Lim
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Seong Hee
authors.initials: SH
authors.lastname: Ahn
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Beom-Jun
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Koh
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D003430:Cross-Sectional Studies; D005260:Female; D005265:Femoral Neck Fractures / Q000097:blood* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D056910:Republic of Korea / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D