Anthropometric and Body Composition Differences Among Genotype Controlled Indigenous Adult Kiwcha Natives Living at Low (230 M) and High Altitude (3,800 M) in Ecuador

Abstract Background: Anthropometric measures have been classically used to understand the impact of environmental factors on the living conditions of individuals and populations. Most reference studies on development and growth in which anthropometric measures were used were carried out in populations that are located at sea level but there are few studies carried out in high altitude populationsObjective: The objective of this study is to evaluate anthropometric and body composition in autochthonous Kiwchas permanently living at low and high-altitude.Methodology: A cross-sectional study of anthropometric and body composition between genetically matched lowland Kiwchas from Limoncocha (230 m) at Amazonian basin and high-altitude Kiwchas from Oyacachi (3,180 m) in Andean highlands. Student’s t-test was used to analyze differences between continue variables and Chi square test was performed to check the association or independence of categorical variables. Fisher´s exact test or Spearman test were used when the variable had evident asymmetries with histograms prior to the selection of the test. Results: Our study shows that low altitude women are shorter and heavier, but these differences are not statistically significant (p value 0.333) on the other hand high altitude men are shorter than their counterparts who live at low altitude with a p value 0.019. In relation to body muscle %, women at high altitudes have less body muscle % (-24.8%) while men at high altitudes have significantly more muscle body mass % (+ 13.5%) than their lowland counterpart. Body fat % is lower among low altitude women (-15.5%) and no differences were found among men.Conclusions: This is the first study to be performed in two genotyped controlled matching populations located at different altitudes. The anthropometric differences vary according to sex, demonstrating that high altitude population are in general lighter and shorter than their low altitude controls. Men at high altitude have more muscled bodies than their lowland counterpart but their body age was older than their real age.