Geometric mean cotinine concentrations and 95% confidence intervals (CI) by smoking restrictions, before and after smoke-free legislation in Scotland
| Restriction group | 2006 | 2007 | Ratio (95% CI) of mean cotinine concentration on 2007:2006 | ||
| Mean (95% CI) cotinine concentration (ng/ml) | No (%) | Mean (95% CI) cotinine concentration (ng/ml) | No (%) | ||
| Complete | 0.14 (0.13 to 0.16) | 994 (47) | 0.07 (0.06 to 0.08) | 985 (50.9) | 0.50 (0.42 to 0.59) |
| Partial | 0.55 (0.47 to 0.63) | 726 (34.3) | 0.49 (0.41 to 0.59) | 674 (34.8) | 0.90 (0.71 to 1.14) |
| None | 1.53 (1.29 to 1.82) | 395 (18.7) | 1.39 (1.17 to 1.67) | 278 (14.4) | 0.91 (0.71 to 1.16) |
| Total | 0.35 (0.32 to 0.38) | 2115 | 0.21 (0.19 to 0.23) | 1937 | 0.61 (0.54 to 0.68) |
Cotinine confirmed non-smokers.
Pupils who live in both, step or single parent families only.
Unadjusted figures.