BMD measurement
The total body (TB) and lumbar spine (LS) BMD were measured using GE
Lunar Prodigy Advance (GE Healthcare, Madison, WI, USA) densitometer.
The areal LSBMD was evaluated on lumbar spine 2-4. Data acquisition and
analyses were performed using enCORE software version 18 (SP1). The
precision for TBBMD measurement was 0.028 g/cm2 and
for LSBMD was 0.028 g/cm2. The z-scores for TBBMD and
LSBMD were generated using the normative data for Thai children and
adolescents.22 As short stature was prevalent in our
study and can produce falsely low BMD, the BMD z-score was expressed as
height-for-age adjusted values as previously
described.23 The BMD z-score of < -2 was
defined as low BMD per the International Society of Clinical
Densitometry (ISCD) pediatric position statement.24