Table 1 Demographics and basic characteristics of the study population

Age

 16–29

12,179(41.8)

6228(43.9)

5951(39.8)

 30–39

12,852(44.1)

5932(41.8)

6920(46.3)

 40–49

3643(12.5)

1794(12.6)

1849(12.4)

 50 and above

474(1.6)

241(1.7)

233(1.6)

 Mean age (SD)

31.78 ± 7.112

31.60 ± 7.273

31.95 ± 6.951

Sex

 Male

13,622(46.7)

6408(45.1)

7214(48.2)

 Female

15,526(53.3)

7787(54.9)

7739(51.8)

Ethnicity

 Han

27,888(95.7)

13,594(95.8)

14,294(95.6)

 Others

1260(4.3)

601(4.2)

659(4.4)

Marriage

 Single

11,015(37.8)

5534(39.0)

5481(36.7)

 Married

17,448(59.9)

8491(59.8)

8957(59.9)

 Divorced or widowed

329(1.1)

170(1.2)

159(1.1)

Education attainment

 Middle school or lower

761(2.6)

476(3.4)

285(1.9)

 High school

3301(11.3)

2080(14.7)

1221(8.2)

 College

22,033(75.6)

10,374(73.1)

11,659(78.0)

 Master and above

3053(10.5)

1265(8.9)

1788(12.0)

Smoking

 Yes

5912(20.3)

2955(20.8)

2957(19.8)

 No

23,236(79.7)

11,240(79.2)

11,996(80.2)

Workplace SF policy

 Yes

21,275(73.0)

10,178(71.7)

11,097(74.2)

 No

7873(27.0)

4017(28.3)

3856(25.8)

Secondhand smoke exposure

 Never

13,858(47.5)

6429(45.3)

7429(49.7)

 1 to 3 days

8906(30.6)

4423(31.2)

4483(30.0)

 4 to 6 days per week

1931(6.6)

981(6.9)

950(6.4)

 Every day

4453(15.3)

2362(16.6)

2091(14.0)

Smoking harm awareness

 Yes

4375(15.0)

1779(12.5)

2596(17.4)

 No

24,772(85.0)

12,416(87.5)

12,356(82.6)

Job position

 Not administrative

19,449(66.7)

9458(66.6)

9991(66.8)

 Administrative

9699(33.3)

4737(33.4)

4962(33.2)