Table 2.

Multiple linear regression analysis showing the association of smoking and PM_2.5 with AHRR cg05575921 methylation in the study participants

Variable	Model 1		Model 2
	β	P value	β	P value
Smoking status (reference: never)
Former	− 0.03909	< 0.0001	− 0.02221	< 0.0001
Current	− 0.17536	< 0.0001	− 0.11578	< 0.0001
P-trend	< 0.0001		< 0.0001
PM2.5	− 0.00141	< 0.0001	− 0.00070	0.0120
Sex (reference: women)
Men	− 0.01870	< 0.0001	− 0.01843	< 0.0001
Age	− 0.00044	0.0145	− 0.00018	0.2636
Exercise (reference: no)
Yes	0.00077	0.8404	0.00052	0.8772
BMI	0.00060	0.2344	0.00014	0.7488
Alcohol drinking (reference: no)
Former	− 0.00512	0.5931	− 0.00821	0.3264
Current	0.00157	0.8318	0.00539	0.4041
Secondhand smoke (reference: no)
Yes	0.00136	0.8100	− 0.00204	0.6793
F2LR3 cg03636183 methylation	–	–	0.71185	< 0.0001

Model 1: not adjusted for F2LR3 cg03636183 methylation. Model 2: adjusted for F2LR3 cg03636183 methylation