title: Variation in cortical density within the cortical shell of individuals across a range in densities and ages.
abstract: OBJECTIVE
  The purpose of this study was to determine variability in cortical volumetric bone density (vBMD) from a single slice tibia image over a range of vBMD readings and ages.
  
  
  METHODS
  Males and females (N=80; aged 6-80) were randomly selected from a previous study. Cortical vBMD at the anterior, posterior, medial, and lateral regions as well as the endocortical, mid-cortical, and pericortical regions of the cortical shell were determined using pQCT.
  
  
  RESULTS
  Mean anterior ROI cortical vBMD (1111±11 mg/cm(3)) was lower than the posterior and lateral ROIs (1169±7 mg/cm(3) and 1151±9 mg/cm(3), respectively), (p<0.05). Individuals with lower overall cortical vBMD and younger individuals had greater vBMD variability within the shell (r=0.37, p=0.004). Difference between anterior and posterior regions was inversely associated with cortical vBMD and jump power (r=0.46, p=0.001). Endocortical vBMD (1080±6 mg/cm) was lower than the mid-cortical and pericortical regions (1152±5 mg/cm(3) and 1147±5 mg/cm, respectively).
  
  
  CONCLUSIONS
  Variability in cortical vBMD was higher among young individuals and those with lower overall cortical vBMD, while lowest in older individuals and men. The anterior ROI had lower mean cortical vBMD than posterior or lateral regions, and endocortical vBMD was lower than the mid- and pericortical regions.
authors: Ethel Austin Martin Program in Human Nutrition, South Dakota State University. Lee.Weidauer@sdstate.edu
authors: L A
authors: LA
authors: Weidauer
authors: T L
authors: TL
authors: Binkley
authors: R
authors: R
authors: Berry
authors: B L
authors: BL
authors: Specker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013977:Tibia / Q000000981:diagnostic imaging* / Q000502:physiology*; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult