title: Diagnostic ability of obesity measures to identify metabolic risk factors in South African women.
abstract: BACKGROUND
  Currently, guidelines for obesity thresholds relating to metabolic risk in South African women have not been established. Therefore, the aim of the study was to investigate the level and diagnostic ability of obesity measures [waist circumference (WC), waist-to-height ratio (WHtR), and visceral adipose tissue (VAT) area] to identify black and white South African women with elevated blood pressure, dyslipidemia, and insulin resistance.
  
  
  METHODS
  Blood pressure, fasting insulin, glucose, and lipids were measured in 241 black and 188 white South African women. Receiver operator characteristic (ROC) curve analyses were performed to determine the diagnostic ability of WC, WHtR, and computer tomography (CT)-derived VAT to identify subjects above metabolic risk thresholds. The Youden index was used to calculate obesity thresholds for metabolic risk variables.
  
  
  RESULTS
  WC, WHtR, and VAT were significant determinants of all metabolic risk variables (P<0.05), and differences in the ROC area under the curve (AUC) between obesity measures were small (≈0.08) for all metabolic risk variables, in both ethnic groups. However, the ROC AUC vales for all obesity measures were greater in white compared to black women (P<0.01). WC and VAT thresholds were lower in black women compared to white women, whereas WHtR thresholds varied less between ethnicities.
  
  
  CONCLUSIONS
  Due to the cost, access, and radiation exposure, CT-derived VAT is not recommended above the use of simple anthropometric measures (WC and WHtR) for the determination of metabolic risk. Furthermore, thresholds of WHtR, due to low variability between ethnicities, may be more useful than WC for ethnic comparisons of risk.
authors: UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Cape Town, South Africa.
authors: Juliet
authors: J
authors: Evans
authors: Lisa
authors: L
authors: Micklesfield
authors: Courtney
authors: C
authors: Jennings
authors: Naomi S
authors: NS
authors: Levitt
authors: Estelle V
authors: EV
authors: Lambert
authors: Tommy
authors: T
authors: Olsson
authors: Julia H
authors: JH
authors: Goedecke