Salivary cotinine concentrations by responses to self-report items on exposure to secondhand smoke in cars and homes
| Median (and IQR) salivary cotinine concentration (ng/mL) | Frequency and percentage cotinine above limit of detection | p Value | ||
|---|---|---|---|---|
| Smoking allowed in car | No (n=1689) | <0.1 (<0.1 to 0.2) | 594 (35.2) | |
| Yes (n=569) | 1.1 (0.4 to 2.2) | 526 (92.4) | <0.001 | |
| Don't know (n=424) | 0.1 (<0.1 to 0.8) | 235 (55.4) | ||
| Don't own a car (n=211) | 1.1 (0.2 to 2.7) | 179 (84.8) | ||
| In a car where someone was smoking yesterday | No (n=2653) | <0.1 (<0.1 to 0.6) | 1320 (49.8) | |
| Yes (n=196) | 1.4 (0.7 to 2.9) | 186 (94.9) | <0.001 | |
| Parent figures smoke in the home | None (n=1781) | <0.1 (<0.1 to 0.1) | 588 (33.0) | |
| Father (n=272) | 0.5 (0.1 to 1.2) | 225 (82.7) | ||
| Mother (n=299) | 1.2 (0.4 to 2.2) | 274 (91.6) | <0.001 | |
| Both (n=406) | 1.8 (1.0 to 3.0) | 396 (96.3) | ||
| Smoking restrictions in the home | Full (n=1557) | <0.1 (<0.1 to 0.1) | 484 (31.1) | |
| Partial (n=672) | 0.5 (0.1 to 1.6) | 534 (79.5) | <0.001 | |
| None (n=337) | 1.7 (0.9 to 2.9) | 319 (94.7) |
p Values from design-adjusted χ2 analyses.