A comparative analysis of lung function and spirometry parameters in genotype-controlled natives living at low and high altitude

Abstract

Background: The reference values for lung function are associated to anatomical and lung morphology parameters, but anthropometry it is not the only influencing factor: altitude and genetics are two important agents affecting respiratory physiology. Altitude and its influence on respiratory function has been studied independently of genetics, considering early and long-term acclimatization. Objective: The objective of this study is to evaluate lung function through a spirometry study in autochthonous Kichwas permanently living at low and high-altitude. Methodology: A cross-sectional study of spirometry differences between genetically matched lowland Kichwas from Limoncocha (230 m) at Amazonian basin and high-altitude Kichwas from Oyacachi (3,180 m) in Andean highlands. Chi-square method was used to analyze association or independence of categorical variables, while Student's t test was applied to comparison of means within quantitative variables. ANOVA, or in the case that the variables didn't meet the criteria of normality, Kruskal Wallis test were used to compare more than two groups. Results: People from Oyacachi (high altitude) showed a higher predicted values than those from Limonocha (low altitude). The FVC and the FEV1 were significantly greater among highlanders than lowlanders (p value < 0.001). The FEV1/FVC was significantly higher among lowlanders than highlanders for men and women. A restrictive pattern was found in 12.9% of the participants. Conclusion: Residents of Oyacachi had greater lung capacity than their peers from Limoncocha, a finding physiologically plausible according to published literature. When analyzing the spirometric patterns obtained in these populations, it was evident that no person had an obstructive pattern, while on the other hand, the restrictive pattern appeared in Limoncocha and Oyacachi populations in 12.9% although it is clear that there is a predominance of this in the individuals belonging to Limoncocha.