FIGURE 1.

When all the exclusion criteria were applied, the total number of excluded subjects is the number shown in the box. The bottom box shows the subjects who are included in the linear mixed effects model analysis. Exclusion based on missing data of key variables: date of birth, sex, length, smoking status, phenotype, α-1-antitrypsin (AAT) therapy status. Exclusion criteria: age <25 years, phenotype not ZZ (Glu342Lys) α-1-antitrypsin deficiency (ZZ-AATD), follow-up data <4 years, baseline post-bronchodilator FEV₁ % predicted value <30% or >65% predicted, lung transplantation, current smokers, stopped smoking ≤6 months prior to inclusion.