title: Racial disparity in fracture risk between white and nonwhite children in the United States.
abstract: OBJECTIVE
  To examine risk factors for fracture in a racially diverse cohort of healthy children in the US.
  
  
  METHODS
  A total of 1470 healthy children, aged 6-17 years, underwent yearly evaluations of height, weight, body mass index, skeletal age, sexual maturation, calcium intake, physical activity levels, and dual-energy x-ray absorptiometry (DXA) bone and fat measurements for up to 6 years. Fracture information was obtained at each annual visit, and risk factors for fracture were examined using the time-dependent Cox proportional hazards model.
  
  
  RESULTS
  The overall fracture incidence was 0.034 fracture per person-year with 212 children reporting a total of 257 fractures. Being white (hazard ratio [HR] = 2.1), being male (HR = 1.8), and having skeletal age of 10-14 years (HR = 2.2) were the strongest risk factors for fracture (all P ≤ .001). Increased sports participation (HR = 1.4), lower body fat percentage (HR = 0.97), and previous fracture in white girls (HR = 2.1) were also significant risk factors (all P ≤ .04). Overall, fracture risk decreased with higher DXA z scores, except in white boys, who had increased fracture risk with higher DXA z scores (HR = 1.7, P < .001).
  
  
  CONCLUSIONS
  Boys and girls of European descent had double the fracture risk of children from other backgrounds, suggesting that the genetic predisposition to fractures seen in elderly adults also manifests in children.
authors.affiliation: Departments of Orthopaedic Surgery and Radiology, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA. twren@chla.usc.edu
authors.forename: Tishya A L
authors.initials: TA
authors.lastname: Wren
authors.forename: John A
authors.initials: JA
authors.lastname: Shepherd
authors.forename: Heidi J
authors.initials: HJ
authors.lastname: Kalkwarf
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
authors.forename: Joan M
authors.initials: JM
authors.lastname: Lappe
authors.forename: Sharon
authors.initials: S
authors.lastname: Oberfield
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Dorey
authors.forename: Karen K
authors.initials: KK
authors.lastname: Winer
authors.forename: Vicente
authors.initials: V
authors.lastname: Gilsanz
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity; D000293:Adolescent; D001741:Black or African American; D000365:Age Determination by Skeleton; D001213:Asian; D015992:Body Mass Index; D002136:Calcium, Dietary; D002648:Child; D015444:Exercise; D005260:Female; D050723:Fractures, Bone / Q000208:ethnology* / Q000209:etiology; D054624:Health Status Disparities; D006306:Health Surveys; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012741:Sexual Maturation; D014481:United States / Q000453:epidemiology; D044465:White People
chemical_list: D002136:Calcium, Dietary