title: Associations between serum 25-hydroxyvitamin D and bone mineral density and proximal femur geometry in Koreans: the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2009.
abstract: The association between 25-hydroxyvitamin D (25(OH)D) levels and bone mineral density (BMD) and proximal femur bone geometry was examined in the Korean population. A positive relationship between skeletal health and 25(OH)D levels was observed. However, there were no significant differences in skeletal health between the groups with 25(OH)D level of 50-75 nmol/L and greater than 75 nmol/L.
  
  
  BACKGROUND
  Vitamin D plays an important role in calcium and phosphate homeostasis and normal mineralization of bone. However, the optimal level of vitamin D for skeletal health has not been clearly established. We analyzed the associations between serum 25(OH)D and BMD and proximal femur bone geometry and determined the optimal 25(OH)D level.
  
  
  METHODS
  This was a cross-sectional study of 10,062 participants (20-95 years, 4,455 men, 5,607 women) in the Fourth Korea National Health and Nutrition Examination Surveys (KNHANES IV) conducted from 2008 to 2009. Participants were divided into groups according to 25(OH)D level (<25, 25-50, 50-75, and ≥75 nmol/L). BMD and proximal femur geometric indices were measured.
  
  
  RESULTS
  The group with 25(OH)D levels of 50-75 nmol/L had greater bone density values, with the exception of the lumbar spine, and also had greater femur neck cortical thickness, cross-sectional area, and cross-sectional moment of inertia, as well as a lesser buckling ratio than the groups with 25(OH)D level of 25-50 nmol/L and less than 25 nmol/L. However, there were no significant differences in BMD and proximal femur geometry properties between the groups with 50-75 nmol/L and greater than 75 nmol/L of 25(OH)D.
  
  
  CONCLUSIONS
  The skeletal outcomes, including BMD and proximal femur geometric indices observed in this study, suggest that serum 25(OH)D levels of 50 to <75 nmol/L are optimal for skeletal health.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea.
authors.forename: S
authors.initials: S
authors.lastname: Hwang
authors.forename: H S
authors.initials: HS
authors.lastname: Choi
authors.forename: K M
authors.initials: KM
authors.lastname: Kim
authors.forename: Y
authors.initials: Y
authors.lastname: Rhee
authors.forename: S K
authors.initials: SK
authors.lastname: Lim
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry / Q000379:methods; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D056910:Republic of Korea / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D