title: Visceral and subcutaneous adiposity measurements in adults: influence of measurement site.
abstract: OBJECTIVE
  Excess abdominal adiposity is a known risk factor for cardiovascular diseases. Computed tomography can be used to examine the visceral (VAT) and subcutaneous (SAT) components of abdominal adiposity, but it is unresolved whether single-slice or multi-slice protocols are needed.
  
  
  METHODS
  Nine computed tomography scans were obtained in the lumbar spine region of 24 adults. The nine slices were obtained at three intervertebral positions (L2-L3, L3-L4, and L4-L5) and at 7 mm above and below these locations. Intra-site and inter-site differences in SAT, VAT, total adipose tissue, and the VAT/SAT ratio were examined using ANOVA and confidence intervals for pairwise differences between means.
  
  
  RESULTS
  Intervertebral SAT values increased from 103.1 +/- 50.9 (standard deviation) cm(2) at L2-L3 to 153.3 +/- 68.8 cm(2) at L4-L5, whereas the corresponding VAT values decreased from 164.3 +/- 125.4 to 126.0 +/- 82.7 cm(2). The VAT/SAT ratio was not constant, decreasing from 1.8 +/- 1.4 to 0.9 +/- 0.7. Repeated-measures ANOVA indicated significant inter- and intra-site differences (p </= 0.02) for SAT, VAT, and the VAT/SAT ratio at L3-L4 and L4-L5 (p < 0.001).
  
  
  CONCLUSIONS
  These differences show the limitation of using a single-slice assessment of abdominal fat distribution, both for a subject and between subjects. Furthermore, the sizeable differences in the intra-site scans indicate that precise repositioning is needed for longitudinal studies. In summary, our findings suggest that a multi-site imaging protocol may provide a more complete assessment of abdominal fat stores and distribution than use of a single site.
authors.affiliation: Body Composition Laboratory, USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates Street, Houston, TX 77030, USA. kellies@bcm.tmc.edu
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Ellis
authors.forename: Birgit
authors.initials: B
authors.lastname: Grund
authors.forename: Fehmida
authors.initials: F
authors.lastname: Visnegarwala
authors.forename: Lisa
authors.initials: L
authors.lastname: Thackeray
authors.forename: Collin G
authors.initials: CG
authors.lastname: Miller
authors.forename: Charles E
authors.initials: CE
authors.lastname: Chesson
authors.forename: Wafaa
authors.initials: W
authors.lastname: El-Sadr
authors.forename: Andrew
authors.initials: A
authors.lastname: Carr
mesh_terms: D050154:Adiposity; D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D015497:HIV-1; D039682:HIV-Associated Lipodystrophy Syndrome / Q000473:pathology; D006801:Humans; D050152:Intra-Abdominal Fat / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009928:Organ Specificity; D050151:Subcutaneous Fat / Q000473:pathology*; D014781:Viscera
chemical_list: D044966:Anti-Retroviral Agents