[Comparison and application of obesity screening indicators in children and adolescents aged 6-18 years in Hangzhou in 2023].

OBJECTIVE

To determine the percentile reference values and reference curves of total body fat percentage in children and adolescents by sex and age, and to evaluate the reliability of different anthropometric indicators in screening for obesity in children and adolescents in order to explore the validity and practicality of a large-scale screening tool for childhood obesity and its desirable thresholds.

METHODS

A total of 5983 children and adolescents aged 6-18 years from six primary and secondary schools were selected by stratified randomised cluster sampling in Hangzhou City in 2023, and their weight, height, waist and hip circumferences were measured, and the children's total body fat content was measured using the bioelectrical resistance-antibody composition analyser. A generalised additive model(GAMLSS) was used to construct a percentile reference curve for children's body fat percentage, and the performance of each anthropometric measure in correctly classifying children and adolescents as obese was assessed using receiver operating characteristic(ROC) curves.

RESULTS

Over the period 6-18 years, body fat percentage in girls tended to increase with age from year to year, whereas in boys it tended to increase and then decrease. Fat mass index was the main factor contributing to the difference in BMI at the same age and sex(the optimal cutoff values were 26.82 and 24.52, with AUC values of 0.988 and 0.992, respectively), and the contribution of fat mass index was greater in those with a higher BMI. BMI, which had the largest area under the curve for both boys and girls, was the best indicator for assessing obesity in children and adolescents; the waist-to-height ratio(WHtR), with small variability and equally large area under curve values(0.980 for boys and 0.970 for girls), could simultaneously meet the requirements of accuracy and practicality for obesity assessment in mass screening of children and adolescents.

CONCLUSION

This study establish the percentile reference value and reference curve of body fat percentage of children and adolescents aged 6-18 years in Hangzhou based on bioelectrical impedance method, and found that WHtR is a simple, effective and practical screening tool for childhood obesity with low variability, which can provide a reference basis for evaluating growth and development and identifying obesity in children aged 6-18 years in this region.