Geometric mean cotinine concentrations and 95% confidence intervals (CI) by smoking restrictions, adjusted for age and FAS, for children 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 (%) | ||
| Children who live with non-smoking parents | |||||
| Complete | 0.12 (0.11 to 0.13) | 808 (71.4) | 0.06 (0.05 to 0.07) | 806 (79.4) | 0.49 (0.42 to 0.57) |
| Partial | 0.19 (0.16 to 0.22) | 280 (24.7) | 0.14 (0.12 to 0.17) | 186 (18.3) | 0.76 (0.58 to 0.98) |
| None | 0.26 (0.16 to 0.41) | 44 (3.9) | 0.24 (0.15 to 0.30) | 23 (2.3) | 0.92 (0.49 to 1.76) |
| Total | 0.14 (0.13 to 0.15) | 1132 | 0.07 (0.06 to 0.08) | 1015 | 0.52 (0.45 to 0.59) |
| Children who live with at least one smoking parent | |||||
| Complete | 0.40 (0.32 to 0.51) | 98 (12.7) | 0.21 (0.17 to 0.26) | 108 (14.8) | 0.52 (0.38 to 0.71) |
| Partial | 1.23 (1.06 to 1.42) | 366 (47.5) | 0.92 (0.78 to 1.08) | 404 (54.4) | 0.75 (0.61 to 0.93) |
| None | 2.05 (1.80 to 2.33) | 307 (39.8) | 1.75 (1.48 to 2.08) | 217 (29.8) | 0.86 (0.69 to 1.06) |
| Total | 1.31 (1.17 to 1.45) | 771 | 0.90 (0.79 to 1.02) | 729 | 0.69 (0.58 to 0.81) |
Cotinine confirmed non-smokers.
Pupils who live in both, step or single parent families only.