Heterogeneity	Publication bias	Meta-regression for gender*	
	Q value	P(Q)	I2 ,%	Fail-safe N	Begg and Mazumdar rank correlation, P	Egger’s regression, P	P(Slope)	
Inspiration								
 %LAA-950 and FEV1 %pred 	11.65	0.11	39.9	451	0.62	0.22	0.16	
 %LAA-950 and FEV1/FVC	10.22	0.12	41.3	614	0.45	0.31	0.71	
MLD and FEV1 %pred	6.08	0.11	50.6	97	0.50	0.14	0.22	
 MLD and FEV1/FVC	8.29	0.02	75.9	172	0.60	0.77	0.05	
WA% and FEV1  %pred	8.50	0.04	64.7	255	0.73	0.60	IS	
Expiration								
 %LAA-950 and FEV1 %pred 	0.81	0.67	0	84	0.12	0.21	0.85	
 %LAA-950 and FEV1/FVC	0.38	0.54	0	IS	IS	IS	IS	
MLD and FEV1 %pred	3.55	0.17	43.6	122	0.12	0.15	0.56	
 MLD and FEV1/FVC	0.05	0.82 	0	IS	IS	IS	IS	

FEV1 %pred = Predicted forced expiratory volume in the first second; FEV1/FVC = FEV1 divided by forced vital capacity; %LAA-950 = Percentage lower attenuation area than -950HU; MLD = Mean lung density; Perc15 = 15 percentile point of lung density; WA% = Wall area percentage; IS = Insufficient study numbers to perform analysis.
*: Percentage of male was considered as moderator variable.