Ultrasonography is not more reliable than anthropometry for assessing visceral fat in obese children

Visceral fat accumulation is a risk factor for obesity-related complications. Waist circumference is used in clinical practice to assess visceral adiposity.

Ultrasound is not superior to waist circumference for assessing visceral obesity in obese children. The optimal site for measuring waist circumference in obese children is at the smallest body circumference between xiphisternum and umbilicus.

Visceral fat accumulation is a well-established risk factor for obesity-related complications. In children, it has not been determined whether ultrasonography is superior to waist measurement for assessing visceral fat. Moreover, the optimal site for waist measurement has not been determined.

In a prospective cohort of 92 severely obese children and adolescents (age 13.9 ± 2.2 years, body mass index z-score 3.29 ± 0.33), we evaluated the performance of ultrasonography and two different methods of waist circumference measurement, using magnetic resonance imaging as the reference standard.

Waist circumference, defined as the smallest body circumference between xiphisternum and umbilicus had the strongest correlation with visceral fat quantity (r = 0.69 all, r = 0.68 girls, r = 0.64 boys). It was not outperformed by ultrasonography (r = 0.60 all, r = 0.62 girls, r = 0.50 boys) and correlated significantly better than the World Health Organization standard for waist measurement, midway between lower margin of the last rib and the crest of the ilium, (r = 0.51 all, r = 0.39 girls, r = 0.46 boys).

Waist circumference measurement, defined as the smallest body circumference between xiphisternum and umbilicus, is the preferred non-invasive technique for daily clinical practice to assess visceral fat accumulation in severely obese children and adolescents. There is no place for ultrasonography for the quantification of visceral fat in this group.