Mid-upper arm circumference as a screening tool for identifying underweight adolescents

Mid-upper arm circumference (MUAC) is a potentially credible alternative method for body mass index (BMI) to assess nutritional status. We aimed to assess the correlation between MUAC and BMI- Z-score and to identify a reliable MUAC cut-off point to detect underweight (BMI- Z-score of < -2 standard deviation) Sudanese adolescents.

A cross-sectional study was conducted in eastern Sudan. After obtaining adolescents' age and sex, their weight, height, and MUAC were measured using the standard procedures. The MUAC (cm) cut-off corresponding to underweight was calculated using receiver operating characteristic (ROC) curve analysis.

In total, 390 adolescents were enrolled in the study and 205 (52.6%) of them were females. The median (interquartile range, IQR) age was 15.1 (14.0-16.3) years. The medians (IQR) of MUAC and BMI- Z-score were 22.0 (20.0-24.0) cm and - 0.62 (-1.5-0.3), respectively. MUAC was positively correlated with BMI Z-score in all participants (r = 0.534, p < 0.001), in females (r = 0.715, p < 0.001), and in males (r = 0.404, p < 0.001). Of the 390 enrolled adolescents, 61(15.6%) were underweight. The MUAC cut-off for underweight was ≤21.2 cm in all participants (Youden's Index, YI = 0.50; sensitivity = 82.0%; specificity = 68.0%, AUROCC = 0.78), in females (YI = 0.66, sensitivity = 86.0%, specificity = 80.0%, AUROCC = 0.87), and in males (YI = 0.32, sensitivity = 80.0%, specificity = 52.0%, AUROCC = 0.69).

MUAC has good accuracy results and can be adopted for community-based screening of underweight adolescents.