Spirometry in Central Asian Lowlanders and Highlanders, a Population Based Study.

Stefanie Ulrich,Konrad E Bloch,Peter G J Burney,Nurgul Toktogulova,Bermet Estebesova,Michael Furian,Gulnara Beishekeeva,Silvia Ulrich,Talant M Sooronbaev

doi:10.3389/fmed.2019.00308

Abstract

Introduction: The purpose of the study was to establish spirometric reference values for a Central Asian population of highlanders and lowlanders.Methods: Spirometries from a population-based cross-sectional study performed in 2013 in rural areas of Kyrgyzstan were analyzed. Using multivariable linear regression, Global Lung Function Initiative (GLI) equations were fitted separately for men and women, and altitude of residence (700–800 m, 1,900–2,800 m) to data from healthy, never-smoking Kyrgyz adults. The general GLI equation was applied: Predicted value=ea0+a1× ln(Height)+a2× ln(Age)+b1× ln(Age100)+b2× ln(Age100)2+b3× ln(Age100)3 +b4× ln(Age100)4+b5× ln(Age100)5Results: Of 2,784 screened Kyrgyz, 448 healthy, non-smoking highlanders (379 females) and 505 lowlanders (368 females), aged 18–91 years, were included. Predicted FVC in Kyrgyz fit best with GLI “North-East Asians,” predicted FEV1 fit best with GLI “Other/Mixed.” Predicted FEV1/FVC was lower than that of all GLI categories. Age- and sex-adjusted mean FVC and FEV1 were higher in highlanders (+0.138l, +0.132l) than in lowlanders (P < 0.001, all comparisons), but FEV1/FVC was similar.Conclusion: We established prediction equations for an adult Central Asian population indicating that FVC is similar to GLI “North-East Asian” and FEV1/FVC is lower than in all other GLI population categories, consistent with a relatively smaller airway caliber. Central Asian highlanders have significantly greater dynamic lung volumes compared to lowlanders, which may be due to environmental and various other effects.

Highlights

The purpose of the study was to establish spirometric reference values for a Central Asian population of highlanders and lowlanders
For highlanders and lowlanders are shown in Supplementary Figures 1, 2
The height of highlanders of both sexes and the weight of female highlanders were significantly lower than corresponding values of lowlanders

Summary

Introduction

The purpose of the study was to establish spirometric reference values for a Central Asian population of highlanders and lowlanders. Ethnic differences in pulmonary function have been frequently reported and spirometry reference equations for various populations and ethnic groups have been published in the past [1,2,3,4,5,6,7]. The Kyrgyz Republic, as an example of Central Asian states, is home to more than six million inhabitants [10] and around 41% of the population live higher than 1,000 m above sea level [11]. While spirometry reference values calculated from measurements in 1,044 Kyrgyz male miners [15] and from Kazak children [16] have been reported, spirometric reference data of a large Central Asian population sample of healthy, non-smoking adults—especially those of women—are lacking. Height, sex and ethnicity, the forced vital capacity (FVC), the forced expiratory volume in one second (FEV1) and the FEV1/FVC ratio have been predicted for five ethnic groups that do not include Central Asians

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Conclusion