DEXA supports the use of BMI as a measure of fatness in young girls

Int J Obes Relat Metab Disord. 1996 Nov;20(11):1014-21.


Objective: To examine the relationship of body fat mass measured by dual energy X-ray absorptiometry (DEXA) to BMI in young girls, according to age and normative BMI percentile groupings.

Design: Cross-sectional observation study.

Setting: Dunedin, an urban town in the South Island of New Zealand.

Subjects: 196 healthy Caucasian girls aged 4-16 y.

Measurements: Body weight, height and BMI, total fat mass and % body fat (by DEXA).

Results: Our BMI percentile standard groupings were < 5 centile (n = 7); 5-50 centile (n = 71); 51-75 centile (n = 50); 76-90 centile (n = 42); 91-95 centile (n = 12); > 95 centile (n = 14). In this whole population sample DEXA-derived fat mass correlates well with BMI (n = 0.934) indicating that BMI accounts for 87.2% of the variance in body fat mass. However, at the extremes of BMI the association is weaker. A nomogram for predicting DEXA fat mass from BMI in girls is presented.

Conclusion: Because DEXA-derived fat mass correlates well with BMI throughout the 'normal' range of BMI (5-95th centiles) our study supports the usefulness of BMI as a simple measure of fatness in girls. Children with BMI values outside the normal BMI range may benefit from more exact body composition assessment using DEXA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon*
  • Adipose Tissue*
  • Adolescent
  • Body Composition*
  • Body Height
  • Body Mass Index*
  • Body Weight
  • Child
  • Child, Preschool
  • Female
  • Humans
  • New Zealand
  • Reference Values