title: Fibroblast growth factor 23, bone mineral density, and risk of hip fracture among older adults: the cardiovascular health study.
abstract: BACKGROUND
  Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that also inhibits calcitriol synthesis.
  
  
  OBJECTIVE
  Our objective was to evaluate the relationships of plasma FGF23 concentrations with bone mineral density (BMD) and hip fracture in community-dwelling older adults.
  
  
  METHODS
  Linear regression and Cox proportional hazard models were used to examine the associations of plasma FGF23 concentrations with BMD and incident hip fracture, respectively. Analyses were also stratified by chronic kidney disease.
  
  
  METHODS
  Participants included 2008 women and 1329 men ≥65 years from the 1996 to 1997 Cardiovascular Health Study visit.
  
  
  METHODS
  Dual x-ray absorptiometry measured total hip (TH) and lumbar spine (LS) BMD in 1291 participants. Hip fracture incidence was assessed prospectively through June 30, 2008 by hospitalization records in all participants.
  
  
  RESULTS
  Women had higher plasma FGF23 concentrations than men (75 [56-107] vs 66 [interquartile range = 52-92] relative units/mL; P < .001). After adjustment, higher FGF23 concentrations were associated with greater total hip and lumbar spine BMD in men only (β per doubling of FGF23 = 0.02, with 95% confidence interval [CI] = 0.001-0.04 g/cm(2), and 0.03 with 95% CI = 0.01-0.06 g/cm(2)). During 9.6 ± 5.1-11.0 years of follow-up, 328 hip fractures occurred. Higher FGF23 concentrations were not associated with hip fracture risk in women or men (adjusted hazard ratio = 0.95, with 95% CI = 0.78-1.15, and 1.09 with 95% CI = 0.82-1.46 per doubling of FGF23). Results did not differ by chronic kidney disease status (P > .4 for interactions).
  
  
  CONCLUSIONS
  In this large prospective cohort of community-dwelling older adults, higher FGF23 concentrations were weakly associated with greater lumbar spine and total hip BMD but not with hip fracture risk.
authors.affiliation: Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Jovanovich
authors.forename: Petra
authors.initials: P
authors.lastname: Bùzková
authors.forename: Michel
authors.initials: M
authors.lastname: Chonchol
authors.forename: John
authors.initials: J
authors.lastname: Robbins
authors.forename: Howard A
authors.initials: HA
authors.lastname: Fink
authors.forename: Ian H
authors.initials: IH
authors.lastname: de Boer
authors.forename: Bryan
authors.initials: B
authors.lastname: Kestenbaum
authors.forename: Ronit
authors.initials: R
authors.lastname: Katz
authors.forename: Laura
authors.initials: L
authors.lastname: Carbone
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lee
authors.forename: Gail A
authors.initials: GA
authors.lastname: Laughlin
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Mukamal
authors.forename: Linda F
authors.initials: LF
authors.lastname: Fried
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
authors.forename: Joachim H
authors.initials: JH
authors.lastname: Ix
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D006620:Hip Fractures / Q000097:blood / Q000209:etiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D016103:Spinal Fractures / Q000209:etiology*
chemical_list: C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23