Objectives
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.
Materials and Methods
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.
Results
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.
Conclusions
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.
The Philippine population prior to European contact is the result of the arrival to the archipelago of different subgroups and the admixture between them. Taking the skull as a complex genotype resulting from both genetic inheritance and the environment, and assuming populations with phenotypic similarity will have a greater phylogenetic relationship, the possibility of studying admixture based on geometric morphometry and cranial measurements is proposed. Sixty-one skulls from a collection from the National Museum of Anthropology in Madrid (MNA, Spain) were studied, all dating from before the 19th century. As a reference, the Howells (1973) database was used.The characterization of the phenotype was carried out using a Microscribe digitizer arm with which 65 landmarks were taken, using them to create 12 craniometric distances. The admixture of the Philippine skull collection from the MNA was evaluated by applying a Discriminant Analysis based on Gaussian finite mixture modeling.Thanks to a principal component analysis, a study of morphospaces was carried out.Additionally, a population inference was made using the Relethford and Blangero model. Finally, the skulls were divided into clusters according to their admixture using the k-means method. The individual admixture of each skull was estimated, and later the collection was divided into three clusters after applying the k-means method. The Relethford and Blangero analysis indicated that the groups created did not have much internal admixture, unlike the Filipino group in the Howells database. Assuming a relative neutrality of the craniofacial characters, it is possible to study the admixture of some individuals from a series of cranial distances. This study is framed in the line of other genetic, linguistic, or morphometric types, which indicate that the Philippine population prior to the 19th century has a great intrapopulation variance, constituting a series of metapopulations within the entire archipelago.
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