Abstract
BMIz-score (BMIz) is commonly used to assess childhood obesity. Whether change in
BMIz score predicts change in visceral fat remains unclear. The objective of the work
was to study changes in visceral fat, cardiovascular fitness (CVF), and metabolic
health over 6 months in children with stable/decreased-BMIz vs. increased-BMIz. Ninety
children with obesity, referred for lifestyle intervention were studied (mean age
11±3.1 years, 50% girls, 22% Hispanic). Assessment included abdominal and total fat
by dual X-ray absorptiometry (DXA), sub-maximal VO2 for CVF, anthropometrics, and fasting insulin, glucose, HDL-C, triglycerides, AST
and ALT at 0 and 6 months. Sixty-three children (70%) showed a stable/decrease in
BMIz over 6 months. There was no significant change in total body fat between groups
(−1.3±2.9% in BMIz-stable/down vs. − 0.6 ± 2.6% BMIz-up, p=0.459); however, BMIz-stable/down
group showed a decrease in visceral fat compared to the BMIz-up group (−258±650 g
vs.+137±528 g, p=0.009). BMIz-stable/down group also demonstrated increased CVF (+1.2 ml/kg/min,
p<0.001), not seen in the BMIz-up group. Neither group had significant changes in
metabolic markers. Preventing BMIz increase in obese children predicts a significant
decrease in visceral fat even if total body fat is unchanged. This is often associated
with increased fitness. Thus, increasing fitness level and keeping BMI stable are
strategic initial goals for obese children.
Key words
BMI - child - visceral fat - VO2 max
