Blood eosinophil level and lung function trajectories: cross-sectional and longitudinal studies in European cohorts

Ida Mogensen; Judith M Vonk; Sara R A Wijnant; Xingwu Zhou; H Marike Boezen; Guy Brusselle; Lies Lahousse; Christer Janson; Andrei Malinovschi

doi:10.1183/23120541.00320-2020

Blood eosinophil level and lung function trajectories: cross-sectional and longitudinal studies in European cohorts

ERJ Open Res. 2020 Oct 5;6(4):00320-2020. doi: 10.1183/23120541.00320-2020. eCollection 2020 Oct.

Authors

Ida Mogensen^{1

2}, Judith M Vonk^{3

4}, Sara R A Wijnant^{5

6

7}, Xingwu Zhou^{1

2}, H Marike Boezen^{3

4}, Guy Brusselle^{5

6

8}, Lies Lahousse^{6

7}, Christer Janson², Andrei Malinovschi¹

Affiliations

¹ Dept of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.
² Dept of Medical Sciences, Lung-, Allergy- and Sleep Research, Uppsala University, Uppsala, Sweden.
³ Dept of Epidemiology, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.
⁴ Groningen Research Institute for Asthma and COPD (GRIAC), University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands.
⁵ Dept of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
⁶ Dept of Epidemiology, Erasmus Medical Centre, Rotterdam, The Netherlands.
⁷ Dept of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.
⁸ Dept of Respiratory Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands.

Abstract

Background: Elevated blood eosinophils have been associated with lower lung function and are believed to be associated with accelerated lung function decline.

Method: Blood eosinophils were measured in four cohorts: <45 years cohort within the Vlagtwedde-Vlaardingen (V&V) study, the Uppsala cohort of the European Community Respiratory Health Survey (ECRHS-Uppsala; <45 years), ≥45 years cohort within the V&V study, and the Rotterdam study (≥45 years). Blood eosinophils at baseline were classified as normal (<300 cells·μL^-1) or elevated (≥300 cells·μL^-1). Lung function was measured at baseline and follow-up with spirometry: forced expiratory volume in 1 s (FEV₁), vital capacity (VC) and their ratio FEV₁/VC. The association between blood eosinophils and lung function was tested cross-sectionally using linear regression and longitudinally using a mixed model, both adjusted for age, sex, height, pack-years smoking and smoking status. Stratified analyses were done for asthma.

Results: Elevated blood eosinophils were associated with lower FEV₁ (regression coefficient -147 mL (95% CI -188 to -105 mL)), VC (-120 mL (-165 to -75 mL)) and FEV₁/VC (-1.3% (-1.9% to -0.6%)) at baseline in the two <45 years cohorts, and with lower FEV₁ (-70 mL (-112 to -27 mL)) and FEV₁/VC (-1.8% (-2.6% to -1.0%)) in the two ≥45 years cohorts. Elevated blood eosinophils were associated with an accelerated decline in FEV₁ (-5.5 mL·year^-1 (95% CI -10.5 to -0.5 mL·year^-1)) and VC (-6.4 mL·year^-1 (-11.26 to -1.5 mL·year^-1)) compared to normal blood eosinophils in the younger asthmatic subjects in the longitudinal studies.

Conclusion: Elevated blood eosinophils are associated with lower lung function in the general population and with an accelerated lung function decline among asthmatic individuals.