Developing waist-to-height ratio cut-offs to define overweight and obesity in children and adolescents.

OBJECTIVE

The waist-to-height ratio (WHtR) assesses abdominal adiposity and has been proposed to be of greater value in predicting obesity-related cardiovascular health risks in children than BMI. The present study aims to develop WHtR cut-offs for overweight and obesity based on the 85th and 95th percentiles for the percentage body fat (%BF) in a cohort of children and adolescents.

DESIGN

Waist circumference (WC), height, triceps and subscapular skinfolds were used to calculate WHtR and %BF. Correlations between WHtR and %BF and WHtR/mid-abdominal skinfold were made. Receiver-operating characteristic (ROC) curve analysis was used to select WHtR cut-offs to define overweight and obesity. Subjects were grouped by WHtR cut-offs, and mean values for anthropometry, blood lipids and blood pressure (BP) variables were compared.

SETTING

Australian primary and secondary schools.

SUBJECTS

A total of 2773 male (M) and female (F) subjects of the 1985 Australian Health and Fitness Survey, aged 8-16 years.

RESULTS

Correlation coefficients between WHtR and %BF were M: r = 0.73, F: r = 0.60, P < 0.01 and WHtR/mid-abdominal skinfold were M: r = 0.78, F: r = 0.65, P < 0.01. WHtR of 0.46(M) and 0.45(F) best identified subjects with > or = 85th percentile for %BF and 0.48(M) and 0.47(F) identified subjects with > or = 95th percentile for %BF. When comparing the highest WHtR group to the lowest, both sexes had significantly higher means for weight, WC, %BF, TG (male subjects only), systolic BP (female subjects only) and lower means for HDL cholesterol (P < 0.05).

CONCLUSIONS

WHtR is useful in clinical and population health as it identifies children with higher %BF at greater risk of developing weight-related CVD at an earlier age.