Validity of self-reported abdominal obesity in Thai adults: A comparison of waist circumference, waist-to-hip ratio and waist-to-stature ratio

Abstract 

Background and aims

Waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-stature ratio (WSR), being common proxy measures of abdominal obesity, are useful tools in epidemiologic studies, but little is known about their validity when the indices are derived from self-reported measurements. We determine and compare the validity of self-reported WC, WHR and WSR in order to identify the optimal index for use in epidemiologic surveys.

Methods and Results

Technician- and self-reported measurements of height, waist and hip circumference were obtained from 613 Thai adults (mean age 35 years). Regarding technician-reported measurements as reference, diagnostic test properties were derived and performances of the indices compared using receiver-operator-characteristic curves and the area-under-the-curve (AUC) analyses. There was good agreement between technician- and self-reported measurements for WC and WSR (concordance correlation coefficients ranged from 0.84 to 0.90) but not for WHR (0.50 in men, 0.45 in women). The sensitivity and specificity of self-reported WC and self-reported WSR as measures of abdominal obesity were superior to those of self-reported WHR in both sexes. AUCs for WC and WSR were comparable (0.93 and 0.92, respectively, in men; 0.88 and 0.87 in women) and significantly higher than for WHR (0.80 in men; 0.76 in women; p<0.0001).

Conclusion

WC and WSR derived from self-reported waist and height measurements are valid methods for determining abdominal obesity. Self-reported measurements should not be used to derive the WHR. In Asian populations, WSR may be the optimal index of abdominal obesity when measurements are derived from self-reports in epidemiologic surveys.

Keywords: Obesity, Abdominal adiposity index, Epidemiologic survey, Sensitivity and specificity, Self-report

Abbreviations: AUC, area-under-the-curve, BMI, body mass index, PPV, positive predictive value, ROC, receiver-operator characteristic, STOU, Sukhothai Thammathirat Open University, TCS, Thai Cohort Study, WC, waist circumference, WHR, waist-to-hip ratio, WSR, waist-to-stature ratio