Table 4.
Logistic regression predicting smoke-free home incidence for all respondents and smokers only (2006–2008)
| Predictors |
All respondents |
Smokers only |
||||||
|---|---|---|---|---|---|---|---|---|
| n | Smoke free (%) | Univariate OR | Multivariate OR | n | Smoke free (%) | Univariate OR | Multivariate OR | |
| Sex | ||||||||
| Female | 2388 | 67 | 1.00 | 1.00 | 599 | 32 | 1.00 | |
| Male | 2842 | 65 | 0.92 (0.82–1.04) | 1.06 (0.91–1.24) | 565 | 24 | 1.47 (1.19–1.94) | 1.39 (1.00–1.93) |
| Age group (years) | ||||||||
| 45–64 | 1872 | 66 | 1.00 | 1.00 | 396 | 25 | 1.00 | 1.00 |
| 16–24 | 264 | 59 | 0.74 (0.59–0.93) | 0.95 (0.65–1.38) | 106 | 36 | 1.64 (1.06–2.55) | 0.97 (0.52–1.79) |
| 25–44 | 1739 | 69 | 1.17 (1.01–1.35) | 1.08 (0.88–1.33) | 477 | 31 | 1.33 (0.96–1.83) | 0.77 (0.51–1.16) |
| 65+ | 1416 | 66 | 1.01 (0.86–1.17) | 1.09 (0.90–1.33) | 185 | 16 | 0.59 (0.35–0.98) | 0.74 (0.41–1.35) |
| Social class | ||||||||
| Skilled manual and non-manual | 2346 | 66 | 1.00 | 1.00 | 567 | 29 | 1.00 | 1.00 |
| Managerial and professional | 1911 | 73 | 1.44 (1.25–1.66) | 0.98 (0.83–1.17) | 290 | 33 | 1.23 (0.88–1.73) | 0.96 (0.66–1.41) |
| Part skilled and unskilled | 1034 | 55 | 0.63 (0.53–0.74) | 0.70 (0.57–0.86) | 307 | 21 | 0.67 (0.46–0.99) | 0.79 (0.51–1.21) |
| Number of cars | ||||||||
| 1 | 2361 | 65 | 1.00 | 513 | 28 | 1.00 | 1.00 | |
| 0 | 1129 | 50 | 0.53 (0.46–0.62) | 0.64 (0.53–0.78) | 359 | 14 | 0.43 (0.29–0.62) | 0.47 (0.30–0.75) |
| 2+ | 1801 | 74 | 1.49 (1.29–1.71) | 1.17 (0.97–1.40) | 292 | 40 | 1.74 (1.27–2.39) | 1.46 (1.00–2.13) |
| Smoking status | ||||||||
| Never | 2444 | 79 | 1.00 | 1.00 | — | — | ||
| Ex | 1683 | 73 | 0.72 (0.62–0.84) | 0.81 (0.68–0.97) | — | — | ||
| Light | 846 | 33 | 0.13 (0.11–0.16) | 0.18 (0.14–0.22) | 846 | 33 | 1.00 | 1.00 |
| Heavy | 318 | 15 | 0.04 (0.03–0.06) | 0.09 (0.06–0.13) | 318 | 15 | 0.34 (0.23–0.49) | 0.47 (0.31–0.72) |
| Number of adults | ||||||||
| 2 | 2842 | 69 | 1.00 | 1.00 | 509 | 31 | 1.00 | 1.00 |
| 1 | 1745 | 58 | 0.61 (0.54–0.69) | 1.04 (0.88–1.23) | 475 | 16 | 0.42 (0.31–0.56) | 0.75 (0.51–1.10) |
| 3+ | 704 | 66 | 0.85 (0.72–1.00) | 1.07 (0.85–1.35) | 180 | 33 | 1.10 (0.78–1.54) | 1.07 (0.69–1.67) |
| Age of youngest child (years) | ||||||||
| No child <16 | 3982 | 64 | 1.00 | 1.00 | 813 | 24 | 1.00 | 1.00 |
| 0–4 | 597 | 77 | 1.85 (1.50–2.29) | 2.33 (1.71–3.19) | 154 | 42 | 2.36 (1.62–3.43) | 2.96 (1.77–4.96) |
| 5–10 | 392 | 66 | 1.09 (0.87–1.35) | 1.17 (0.87–1.58) | 115 | 29 | 1.29 (0.81–2.06) | 1.34 (0.77–2.33) |
| 11–15 | 320 | 71 | 1.34 (1.04–1.71) | 1.42 (1.03–1.97) | 82 | 41 | 2.18 (1.35–3.52) | 1.54 (0.94–2.52) |
| Year | ||||||||
| 2006 | 1833 | 61 | 1.00 | 1.00 | 444 | 27 | 1.00 | 1.00 |
| 2007 | 1785 | 67 | 1.26 (1.09–1.45) | 1.30 (1.09–1.56) | 393 | 29 | 1.14 (0.82–1.57) | 1.19 (0.82–1.71) |
| 2008a | 1673 | 72 | 1.58 (1.36–1.83) | 1.58 (1.31–1.90) | 327 | 30 | 1.18 (0.83–1.66) | 1.22 (0.81–1.83) |
| Knowledge of SHS illnesses | 1.29 (1.26–1.32) | 1.18 (1.14–1.21) | 1.16 (1.11–1.22) | 1.10 (1.04–1.16) | ||||
| Agreement with restrictions | 2.75 (2.52–2.99) | 1.78 (1.61–1.97) | 1.87 (1.60–2.19) | 1.64 (1.35–1.97) | ||||
The continuous predictors, knowledge and agreement with restrictions in public places produce a multiplier that describes the ORs of the outcome occurring for each unit increase in the predictor variable. For all categorical variables, the OR describes a multiplicative change compared with the reference category.
aThe 2008 data were collected in February and March 2009 due to a sampling error in October and November 2008.