Table 2.

Univariate and multivariate linear regression analyses for ACE2 expression of AMs.

Covariablesb	Univariable			Multivariablea
	β-coefficient	95% CI	P-value	β-coefficient	95% CI	P-value
Age (years)	− 0.001	− 0.027–0.024	0.899	0.012	− 0.019–0.044	0.435
BMI	− 0.059	− 0.138–0.020	0.141	− 0.028	− 0.122–0.065	0.543
Male	0.197	− 0.511–0.906	0.579	− 0.447	− 1.454–0.560	0.376
Current smoker	0.660	0.042–1.279	0.037	0.791	0.019–1.562	0.045
COPD	0.489	− 0.141–1.119	0.126	0.543	− 0.366–1.451	0.235
Lung cancer	− 0.098	− 0.728–0.533	0.757	− 0.628	− 1.391–0.136	0.105
CVD	− 0.293	− 1.026–0.440	0.426	− 0.304	− 1.032–0.425	0.321
DM	− 0.182	− 1.002–0.638	0.657	0.043	− 0.826–0.912	0.921
RAAS inhibitor	0.233	− 0.869–1.334	0.673	0.720	− 0.487–1.928	0.236

ACE2 angiotensin converting enzyme 2, AM alveolar macrophage, BMI body mass index, COPD chronic obstructive pulmonary disease, CVD cardiovascular disorder, DM diabetes mellitus, RAAS Renin–angiotensin–aldosterone.

^aAdjusted age, BMI, male, current smoker, COPD, lung cancer, hypertension, DM, RAAS inhibitor.

^bReferences for covariables: male (male versus female), current smoker (current smoker vs non-current smoker), COPD (yes versus no), lung cancer (yes versus no), CVD (yes versus no), DM (yes versus no), RAAS inhibitor (use versus no use). Age and BMI were calculated as continuous variables.