Table S2.

General linear model for BPIFB1 mRNA expression

Parameter	B	Standard error	t	Significance
Intercept	−2.8	1.878	−1.491	0.14
Age	0.001	0.029	0.05	0.96
Gender
Male	0.113	0.562	0.201	0.841
Female	0a
Inhaled corticosteroids
Inhaled corticosteroid use	0.347	0.712	0.487	0.627
No inhaled corticosteroid use	0a
Smoking status
Yes	0.552	0.561	0.984	0.328
No (ex-smoker or never-smoker)	0a
COPD status
COPD III–IV	3.237	1	3.236	0.002
COPD II	0.307	0.647	0.475	0.636
Without COPD	0a

Notes:

^aReference parameter is set to 0. Linear regression analysis, where the natural logarithm of the mRNA expression of BPIFB1 is designated as the dependent variable; gender as a fixed factor; COPD status, smoking status, and inhaled corticosteroids as random factors; and age as a covariate.

Abbreviation: COPD, chronic obstructive pulmonary disease.