Table 3.

Multiple linear regression showing the association between living in PM_2.5 areas and AHRR (cg05575921) methylation

Variable	Model 1		Model 2
	β	P value	β	P value
Area (reference: Northern)	–	–	–	–
North-Central	− 0.00274	0.503	− 0.0028	0.947
Central	− 0.01003	0.009	− 0.01069	0.009
Southern	− 0.01480	< .001	− 0.01487	< .001
P trend	< .001			< .001
Sex (reference: women)
Men	− 0.01491	< .001	− 0.01413	< .001
Age	− 0.00023	0.085	− 0.00022	0.114
Alcohol Drinking (reference: no)
Former	− 0.01041	0.358	− 0.01497	0.238
Current	− 0.00532	0.475	− 0.00424	0.609
Exercise (reference: no)
Yes	− 0.00199	0.490	− 0.00180	0.552
BMI	− 0.00009	0.819	− 0.00005	0.906
SHS (reference: no)			–	–
Yes	− 0.00119	0.796	–	–

Model 1 included SHS in the analysis, model 2 excluded SHS from the analysis, SHS second-hand smoke