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Describing the children's body shape by means of Geometric Morphometric techniques
Laura Medialdea1,2, Cayetana Bazaco1, Manuel Domingo D'Angelo Del Campo2,3
1Technical Department, Action Against Hunger Foundation (AAH), Madrid, Spain.
Insights
Geometric Morphometrics reveals significant body shape and size differences in children under five. These variations are linked to age and population origin, offering insights into child development.
Area of Science:
- Human biology
- Anthropometry
- Biometrics
Background:
- Childhood growth involves significant changes in body mass, size, and shape.
- Understanding these developmental changes is crucial for assessing health and nutritional status.
Purpose of the Study:
- To apply Geometric Morphometrics (GM) for visualizing and quantifying body shape differences in healthy children aged 6-59 months.
- To analyze shape variations in relation to age, sex, and population origin.
Main Methods:
- Utilized anthropometrical measurements (weight, height, arm circumference) for nutritional status assessment.
- Applied GM by identifying 36 anatomical landmarks and 108 semi-landmarks on 258 Senegalese and Spanish children.
- Developed a specific protocol for child positioning, photography, landmark digitization, and image processing.
Main Results:
- Significant differences in body shape and size were observed across age, sex, and population origin before and after size correction.
- Ontogenetic (age-related) effects persisted in size even after size-effects correction.
- Principal Component Analysis (PCA) revealed age-related differences in PC1 and population origin in PC2 before size correction; post-correction, population differences were primarily along PC1.
Conclusions:
- Geometric Morphometrics is effective for studying anterior whole-body shape changes in children under five.
- GM allows precise description of shape variations influenced by age and population origin, contributing to developmental studies.
Introduction:
Large shape variations take place during the growth process of children, including quantitative mass and size increase plus qualitative changes in their body shape. The aim of the present study is to apply Geometric Morphometric techniques in order to visualize and quantify such body shape differences in healthy children aged 6-59 months with optimal nutritional status.
Materials And Methods:
Anthropometrical measurements of weight, height, and middle-upper arm circumference were used to assess nutritional status on a sample of 258 Senegalese (n = 154) and Spanish (n = 104) children. A set of 36 anatomical and/or osteologically-based landmarks were identified on the body of the children along with 108 semi-landmarks used to capture curvature attributes on the frontal view of the body image. A specific method was developed to place and photograph children, as well as to locate landmarks, treat images and calculate semi-landmarks. Shape differences among children were analyzed in terms of age, sex, and population origin, taking into consideration allometry effects.
Results:
Our results indicate significant differences in shape and size for all the three factors under study before removing size effect (p < .0001), and in shape after the size correction (p < .01). Only the ontogenetic effect persisted in the size of studied individuals after size-effects correction (p < .0001). Morphometric significant differences were described regarding age for PC1 and population origin in PC2 before removing size effect. Between-population morphometric differences were sorted along PC1 after size correction.
Discussion:
Geometric Morphometric techniques are useful to study morphometric changes in the anterior whole-body view of children under 5 years old, allowing a precise description of shape changes observed when age and population origin are considered.