Relative risk ratios and 95% confidence intervals (CI) for proportion of pupils reporting partial and no restrictions (vs complete restrictions) in their home by survey year, number of smoking parents and family affluence, Scotland
| Effect | Relative risk ratios (RR) | |
| Partial vs complete | None vs complete | |
| RR (95% CI) | RR (95% CI) | |
| Survey year | ||
| 2007 | 0.75 (0.63 to 0.89) | 0.50 (0.40 to 0.63) |
| 2006 | 1.00 (–) | 1.00 (–) |
| Parental smoking | ||
| Both parents smoke | 18.29 (13.26 to 25.22) | 104.73 (70.61 to 155.33) |
| Mother only smokes | 17.18 (12.80 to 23.06) | 78.17 (53.61 to 113.96) |
| Father only smokes | 6.80 (5.26 to 8.80) | 22.96 (15.96 to 33.01) |
| Neither parent smokes | 1.00 (–) | 1.00 (–) |
| Family affluence | ||
| Low | 1.89 (1.53 to 2.33) | 3.28 (2.43 to 4.43) |
| Medium | 1.29 (1.06 to 1.58) | 1.80 (1.33 to 2.44) |
| High | 1.00 (–) | 1.00 (–) |
| Age | 0.81 (0.63 to 1.03) | 0.78 (0.56 to 1.07) |
Cotinine confirmed non-smoking pupils who reported living with both parents, step or single parents.