Serum albumin was also linearly and positively correlated with FEV 1 in those who had not had respiratory disease (β = 163.86, 95% CI = 98.00–229.73, p < 0.0001), and the correlation was similar in both groups (P-interaction = 0.256) (Supplementary Table S6, Figure 4E). This evidence concerns the gene ALB and respiratory system disorder.