Self-reported waist circumference for classifying children with cardiovascular risk

Abstract

Objective : The objectives of this study were two-fold, (1) to validate the self-reported waist circumference (SRWC) against assessor measured waist circumference (MWC) and (2) to evaluate the accuracy of SRWC in classifying children (i) with cardiometabolic risk factors (CMRFs) clustering and (ii) overweight/obese status. Methods : A cross-sectional cluster random sample aged 6-18 years with the self-reported body weight (BW) and height (BH) and waist circumference (WC) were used for data analysis. Children were given a self-administrated questionnaire including questions of demographic data and anthropometric values to bring home for completion. They were asked to return the questionnaire and fast themselves for at least 8 hours on the day of the survey. Anthropometric measures and blood pressure were taken by trained research staff. Fasting blood samples were collected for the measurement of fasting plasma glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol. Results : A total of 515 boys and 711 girls who had self-reported waist circumference data were eligible to enter data analysis. The agreement between SRWC and MWC was assessed by intra-class correlation coefficient (ICC) and it ranged from 0.77 to 0.87. The SRWC values to classify children with a clustering of CMRFs exhibited moderate to moderately high sensitivity (95% CI) [68%(0.43-0.87) for boys and 84%(0.60-0.97) for girls] and specificity [70%(0.66-0.74) for boys and 72%(0.68-0.75) for girls]. The area under the receiver operating characteristics [AUC-ROCs (95% CI)] ranged from acceptable to excellent [from 0.76(0.68-0.84) for boys to 0.83(0.76-0.90) for girls] in classifying children with a clustering of CMRFs. The SRWC values to classify overweight/obesity children showed moderately high sensitivity [74%(0.66-0.81) for boys and 77%(0.69-0.84) for girls] and specificity [78%(0.74-0.82) for boys and 82%(0.79-0.85) for girls]. The AUC-ROCs (95% CI) ranged from acceptable to excellent [from 0.84(0.80-0.88) to 0.84(0.79-0.88)] in classifying children with a clustering of CMRFs and overweight/obesity. Conclusion : SRWC shows high validity to detect MWC and could be used as a screening tool for classifying children with a clustering of CMRFs and overweight/obesity status in Hong Kong Chinese children.