Differences in wasting assessment through Middle-Upper Arm Circumference (MUAC) adjusted by sex, age and geographic origin for children aged 6-59 months: New reference based on anthropometric surveys from 22 low-and-middle-income countries.

Abstract

The Middle Upper Arm Circumference (MUAC) bracelet is a widely used instrument in public health assessments and humanitarian assistance projects. The WHO guidelines present a universal cut-off point of 115 mm to determine whether a child has severe acute malnutrition. The objective of this study is to analyze the existing differences in the MUAC for boys and girls aged between 6 and 59 months, from 22 countries distributed in three different continents, in contrast to the use of this single cut-off point. In addition, the creation of MUAC growth charts is presented for reference use. This study was carried out with a database developed by Action Against Hunger, composed, after the data pre-processing phase, of 97 921 individuals without anthropometric failure from African, Asian, and American continents. MUAC measurements were compared between countries, dividing by sex and age groups. A k-means method was used to create country clusters to allow comparisons and the variability was resumed using a Principal Component Analysis. For each cluster, growth curves were created and smoothed using the LOESS method. Our research has revealed the existence of differences in the MUAC between countries in both, males and females, although with different trends. The evidence was confirmed with the creation of two clusters using the k-means method, which, when graphically represented by the Principal Component Analysis, showed that the MUAC was clearly different. There were also differences between males and females within each cluster, where growth curves did not overlap in any age group. All statistical analysis indicate that there are differences in the MUAC values for children without anthropometric failure between countries, but also between sexes. With this research, a new reference is proposed that consider the existing variability between human populations to improve the precision in the determination of severe acute malnutrition in children.