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


METHODS
Cross-sectional observation study.


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


METHODS
196 healthy Caucasian girls aged 4-16 y.


METHODS
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.


CONCLUSIONS
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.
Goulding
A
A
Department of Medicine, University of Otago Medical School, Dunedin, New Zealand.
Gold
E
E
Cannan
R
R
Taylor
R W
RW
Williams
S
S
Lewis-Barned
N J
NJ
D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D001823:Body Composition; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D009520:New Zealand; D012016:Reference Values