Mid-Upper-Arm Circumference and Arm-to-Height Ratio to Identify Obesity in School-Age Children

Background In resource-poor settings, anthropometric parameters are evaluated as potential alternatives to the body mass index (BMI) for detecting overweight and obesity in children. To this end, the mid-upper arm circumference (MUAC) and the mid-upper arm circumference to height ratio (AHtR) were evaluated as proxies to BMI in Thai school-age children.

Study design An observational, cross-sectional study was performed on school-aged children.

Participants Children in grades 1 through 6 at all public elementary schools in the Ongkharak district, Nakhon Nayok, Thailand during May and June 2013 were included. This is a rural district with low per capita income.

Methods Weight, height, and MUAC were measured in school-age children and analyzed to identify optimal cut-off values for MUAC and AHtR for detection of overweight and obesity in comparison to BMI. Receiver operating characteristic (ROC) curve analysis determined the validity of MUAC and AHtR use.

Results Data from 3,618 children, aged 6.0–12.99 years, were analyzed. MUAC correlated with age and height (P<0.001), but especially with body weight (r = 0.888 to 0.914) and BMI (r = 0.859 to 0.908) in both genders, while AHtR correlated with body weight and BMI (P < 0.001), but not with age. Cut-off values of MUAC for obesity diagnosis ranged from 18.9 to 25.5 cm for boys and from 19.8 to 25.4 cm for girls. Accuracy was excellent for both boys (AUC = 0.952–0.991) and girls (AUC = 0.917–0.990). Cut-off of MUAC for overweight diagnosis ranged from 17.2 to 22.4 cm for boys (AUC = 0.883–0.965) and from 18.0 to 23.2 cm for girls (AUC = 0.905–0.931). AHtR cut-off values for obesity and overweight diagnosis at 0.16 and 0.145, respectively, were determined with excellent diagnostic accuracy (AUC ranged from 0.920 to 0.975).

Conclusion MUAC and AHtR were reliable tools to detect overweight and obesity in Thai school-age children. Cut-off points for MUAC were age-and gender-specific, while AHtR at 0.16 and 0.145 were the optimal values for both genders, independent of age. These anthropometric measurements showed excellent accuracy in predicting overweight and obesity with high specificity and sensitivity.