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

OBJECTIVE To evaluate the performance of mid-upper arm circumference (MUAC) to identify thinness in the late adolescence period (aged 15-19 years) in Ethiopia. DESIGN We conducted a school-based cross-sectional study. The receiver operating characteristics curve was used to examine the validity of MUAC compared with BMI Z-score to identify adolescents with thinness (BMI Z-score <-2 sd). SETTINGS Fifteen high schools (grade 9-12) located in Addis Ababa, Ethiopia. PARTICIPANTS A total of 851 adolescent (456 males and 395 females) were included in the study. RESULTS The prevalence of thinness and severe thinness among high-school adolescents in Addis Ababa was 9·5 % (95 % CI 7·7, 11·7 %). The overall AUC for MUAC against BMI Z-score <-2 SD was 0·91 (95 % CI 0·88, 0·93). The optimal MUAC cut-offs to identify thinness were 23·3 cm for males and 22·6 cm for females. These cut-off points give high sensitivity and specificity for both males (a sensitivity of 87·9 % and a specificity of 75·9 %) and females (a sensitivity of 100 % and a specificity 88·2 %). CONCLUSIONS MUAC has a comparable level of accuracy with BMI Z-score to identify thinness in adolescents aged 15-19 years. Hence, MUAC could be used as an alternative tool for surveillance and screening of thinness among adolescents aged 15-19 years. The optimum cut-off proposed by this study may incorrectly include a large number of adolescents when used in a relatively well-nourished population. In this situation, it would be necessary to choose a cut-off with greater positive predictive value.