title: Bone fragility contributes to the risk of fracture in children, even after moderate and severe trauma.
abstract: We prospectively examined whether the relationship between skeletal fragility and fracture risk in children 9.9 +/- 0.3 (SD) yr is affected by trauma level. Bone size relative to body size and humeral vBMD showed similar inverse relationships with fracture risk, irrespective of whether fractures followed slight or moderate/severe trauma.
  
  
  BACKGROUND
  Fracture risk in childhood is related to underlying skeletal fragility. However, whether this relationship is confined to low-trauma fractures or whether skeletal fragility also contributes to the risk of fracture caused by higher levels of trauma is currently unknown.
  
  
  METHODS
  Total body DXA scan results obtained at 9.9 yr of age were linked to reported fractures over the following 2 yr in children from the Avon Longitudinal Study of Parents and Children. DXA scan results that were subsequently derived included total body less head (TBLH) bone size relative to body size (calculated from TBLH area adjusted for height and weight) and humeral volumetric BMD (vBMD; derived from subregional analysis at this site). Trauma level was assigned using the Landin classification based on a questionnaire asking about precipitating causes.
  
  
  RESULTS
  Of the 6204 children with available data, 549 (8.9%) reported at least one fracture over the follow-up period, and trauma level was assigned in 280 as follows: slight trauma, 56.1%; moderate trauma, 41.0%; severe trauma, 2.9%. Compared with children without fractures, after adjustment for age, sex, socioeconomic status, and ethnicity, children with fractures from both slight and moderate/severe trauma had a reduced bone size relative to body size (1133 cm(2) in nonfractured children versus 1112 cm(2) for slight trauma fractures, p < 0.001; 1112 cm(2) for moderate/severe trauma fractures, p = 0.001) and reduced humeral vBMD (0.494 g/cm(3) in nonfractured children versus 0.484 g/cm(3) for slight trauma fractures, p = 0.036; and 0.482 g/cm(3) for moderate/severe trauma fractures, p = 0.016).
  
  
  CONCLUSIONS
  Skeletal fragility contributes to fracture risk in children, not only in fractures caused by slight trauma but also in those that result from moderate or severe trauma.
authors.affiliation: Clinical Science at South Bristol, University of Bristol, Bristol, United Kingdom.
authors.forename: Emma M
authors.initials: EM
authors.lastname: Clark
authors.forename: Andy R
authors.initials: AR
authors.lastname: Ness
authors.forename: Jon H
authors.initials: JH
authors.lastname: Tobias
mesh_terms: D015502:Absorptiometry, Photon; D015519:Bone Density / Q000502:physiology; D002648:Child; D015331:Cohort Studies; D015897:Comorbidity; D004522:Educational Status; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011446:Prospective Studies; D044469:Racial Groups / Q000706:statistics & numerical data; D012307:Risk Factors; D017678:Sex Distribution; D013124:Spinal Injuries / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D013718:Tensile Strength; D006113:United Kingdom / Q000453:epidemiology; D014947:Wounds and Injuries / Q000453:epidemiology*