Table 1 Sample characteristics and SHS exposure at home, USA 2014^a

Age

p = 0.350

p = 0.548

p = 0.221

 9–12 years

4,461 (20.4)

1,936 (43.4)

997 (24.4)

113 (3.5)

 13–15 years

9,774 (44.7)

4,338 (44.4)

2,125 (24.2)

245 (3.5)

 16–17 years

5,753 (26.3)

2,571 (44.7)

1,259 (24.2)

127 (3.1)

 18+ years

1,862 (8.5)

851 (45.7)

440 (25.8)

33 (2.5)

Sex

p = 0.462

p = 0.017

p = 0.226

 Male

11,150 (51.2)

4,921 (44.1)

2,402 (23.6)

282 (3.5)

 Female

10,645 (48.8)

4,751 (44.6)

2,401 (25.1)

233 (3.1)

Usage of tobacco products

p < 0.001

p < 0.001

p < 0.001

 Tried smoking

6,591 (30.6)

4,029 (61.1)

1,844 (33.9)

262 (6.8)

 Never tried smoking

14,932 (69.4)

5,396 (36.1)

2,950 (21.0)

251 (2.2)

Cigarette smoking status (past 30 days)

p < 0.001

p < 0.001

p < 0.001

 Smoking

1,392 (6.5)

999 (71.8)

463 (42.8)

44 (6.6)

 Not smoking

20,108 (93.5)

8,447 (42.0)

4,285 (23.3)

461 (3.2)

Reaction to best friend offering a cigarette

p < 0.001

p < 0.001

p < 0.001

 Starting to smoke

2,492 (11.4)

1,633 (65.5)

717 (35.7)

86 (6.2)

 Not starting to smoke

19,336 (88.6)

8,034 (41.5)

4,095 (23.0)

426 (3.0)

Judgement of harm caused by smoking

p < 0.001

p < 0.001

p < 0.001

 No or little harm

10,241 (47.9)

4,887 (47.7)

2,470 (27.1)

276 (4.0)

 A lot of harm

11,140 (52.1)

4,449 (39.9)

2,325 (22.7)

238 (2.9)

Thought about harmful chemicals in tobacco products

p < 0.001

p < 0.001

p < 0.001

 Rarely or never

14,088 (66.7)

5,639 (40.0)

2,955 (22.9)

322 (3.1)

 Sometimes

4,040 (19.1)

1,838 (45.5)

988 (27.5)

102 (3.8)

 Often or very often

2,990 (14.2)

1,590 (53.2)

848 (32.9)

91 (5.0)

Receiving advertisements for tobacco products on the internet

p < 0.001

p < 0.001

p < 0.001

 Rarely or never

14,088 (51.6)

4.251 (40.0)

2,244 (23.1)

239 (3.1)

 Sometimes

4,040 (33.4)

2.978 (43.4)

1.583 (25.6)

163 (3.4)

 Most of the time

3,085 (15.0)

1.672 (54.2)

835 (31.5)

97 (5.1)