From: Smoking in cars in England: a study of school students in an English city
Variable | Number of students (% travel in car where smoking allowed) | Univariable model | Multivariable model | ||||
---|---|---|---|---|---|---|---|
Odds ratio | Confidence interval | P-value | Odds ratio | Confidence interval | P-value | ||
Sex | |||||||
Boy | 2,072 (33.6) | 1.00 | 0.044 | ||||
Girl | 2,100 (37.3) | 1.17 | 1.02-1.35 | ||||
Missing | 20 (40.0) | 1.32 | 0.67-2.59 | ||||
School year | |||||||
Year 7 | 623 (31.0) | 1.00 | 0.016 | ||||
Year 8 | 1,078 (35.4) | 1.22 | 0.91-1.65 | ||||
Year 9 | 1,023 (34.9) | 1.19 | 0.87-1.63 | ||||
Year 10 | 1,027 (36.1) | 1.26 | 0.98-1.61 | ||||
Year 11 | 430 (41.9) | 1.60 | 1.10-2.34 | ||||
Missing | 11 (45.6) | 1.86 | 0.33-10.47 | ||||
Deprivation | |||||||
V (least deprived) | 1,040 (26.6) | 1.00 | <0.001 | 1.00 | 0.009 | ||
IV | 446 (33.2) | 1.37 | 1.05-1.78 | 1.13 | 0.87-1.46 | ||
III | 550 (37.5) | 1.65 | 1.24-2.20 | 1.23 | 0.96-1.57 | ||
II | 501 (36.9) | 1.61 | 1.30-2.00 | 1.15 | 0.90-1.48 | ||
I (most deprived) | 507 (48.5) | 2.60 | 1.55-4.36 | 1.58 | 1.23-2.03 | ||
Missing | 1,148 (37.1) | 1.63 | 1.19-2.21 | 1.05 | 0.86-1.27 | ||
Parental smoking | |||||||
Neither parent smokes | 2,856 (24.4) | 1.00 | <0.001 | 1.00 | <0.001 | ||
One parent smokes | 911 (55.4) | 3.85 | 3.31-4.48 | 2.41 | 2.03-2.87 | ||
Both parents smoke | 395 (70.9) | 7.54 | 5.92-9.61 | 3.37 | 2.60-4.38 | ||
Missing | 30 (20.0) | 0.77 | 0.35-1.70 | 0.60 | 0.24-1.51 | ||
Sibling smoking | |||||||
None smokes | 3,658 (32.7) | 1.00 | <0.001 | 1.00 | 0.006 | ||
At least one smokes | 504 (56.9) | 2.73 | 2.09-3.55 | 1.36 | 1.10-1.70 | ||
Missing | 30 (20.0) | 0.52 | 0.25-1.06 | Omitted due to collinearity | |||
Smoking in the main home | |||||||
Not allowed | 3,495 (27.9) | 1.00 | <0.001 | 1.00 | <0.001 | ||
Allowed | 660 (74.9) | 7.70 | 6.99-8.49 | 3.89 | 3.14-4.81 | ||
Missing | 37 (54.1) | 3.05 | 1.90-4.88 | 2.32 | 1.16-4.66 | ||
Friend smoking | |||||||
None | 1,390 (24.0) | 1.00 | <0.001 | 1.00 | <0.001 | ||
One or two | 594 (39.4) | 2.06 | 1.72-2.47 | 1.67 | 1.33-2.09 | ||
Three or more | 1,179 (48.9) | 3.03 | 2.43-3.78 | 2.09 | 1.73-2.51 | ||
Not sure | 1,004 (33.7) | 1.61 | 1.32-1.96 | 1.34 | 1.10-1.62 | ||
Missing | 25 (28.0) | 1.23 | 0.60-2.52 | 0.93 | 0.36-2.44 |