Wrist circumference as a novel predictor of obesity in children and adolescents: the CASPIAN-IV study.

Background: Recent studies have discussed the application of wrist circumference as an easy-to-use predictor of general and abdominal obesity. The aim of the current study is to evaluate the association of wrist circumference with generalized and abdominal obesity and to determine its sex- and age-specific optimal cutoff points in association with generalized and abdominal obesity in a national sample of pediatric population. Methods: This nationwide survey was conducted among 14,880 students, aged 6-18 years, selected through a multistage, random cluster sampling method from rural and urban areas of 30 provinces in Iran from 2011 to 2012. Anthropometric indices (weight, height, wrist circumference, waist circumference [WC], hip circumference [HC]) were measured by standard protocols using calibrated instruments. Body mass index (BMI) and waist-to-height ratio (WHtR) were calculated. By considering the area under the curve (AUC) of the receiver operator characteristic (ROC) curves, we evaluated the association of wrist circumference with obesity indices and determined its sex- and age-specific optimal cutoff points in association with obesity. AUC: 0.5, AUC: 0.5-0.65 and AUC: 0.65-1.0 were interpreted as equal to chance, moderately and highly accurate tests, respectively. Results: Overall, 13,486 children and adolescents with a mean age of 12.47 +/- 3.36 years completed the study (participation rate of 90.6%). In both genders, wrist circumference had a significant correlation with anthropometric measures including weight, height, BMI, WC, HC and WHtR. In all age groups and both genders, wrist circum-ference performed relatively well in classifying individuals into overweight (AUC: 0.67-0.75, p < 0.001), generalized obesity (AUC: 0.81-0.85, p < 0.001) and abdominal obesity (AUC: 0.82-0.87, p < 0.001). Conclusions: Wrist circumference is suggested to be a useful index for assessing excess weight in the pediatric age group. Its easy measurement without the need of calculation ratios might make it as a routine measurement in daily clinical practice and in large epidemiological studies.