Table 6.
Effects of household environmental tobacco smoke (ETS) exposure on asthma, stratified by age at asthma diagnosis
| Early-onset asthma† | Late-onset asthma‡ | |||
|---|---|---|---|---|
| OR | 95%CI | OR | 95%CI | |
| ETS | ||||
| In utero exposure | 1.67 | (0.93,2.99) | 1.49 | (0.69,3.19) |
| Currently | 1.15 | (0.87,1.52) | 1.07 | (0.74,1.57) |
| Previous only | 0.70 | (0.32,1.53) | 0.85 | (0.31,2.35) |
| ETS sources | ||||
| Dad | 1.05 | (0.79,1.41) | 1.13 | (0.77,1.66) |
| Mom | 1.60 | (0.85,2.99) | 0.92 | (0.33,2.58) |
| Number of smokers | ||||
| 0 | 1 | 1 | ||
| 1 | 0.72 | (0.42,1.24) | 0.74 | (0.38,1.46) |
| 2 | 0.49 | (0.22,1.10) | 0.86 | (0.34,2.17) |
| ≧ 3 | 2.80 | (1.27,6.17) | 2.07 | (0.73,5.88) |
| p value for trend | 0.75 | 0.31 | ||
| Currently amount of ETS* | ||||
| 0 | 1 | 1 | ||
| ≦ 10 | 0.86 | (0.56,1.32) | 0.82 | (0.46,1.44) |
| > 10 | 1.51 | (0.85,2.66) | 1.53 | (0.73,3.21) |
| p value for trend | 0.20 | 0.39 | ||
| Percent of ETS** | ||||
| 0 | 1 | 1 | ||
| ≦ 20% | 0.77 | (0.50,1.18) | 0.86 | (0.49,1.52) |
| > 20% | 1.61 | (1.02,2.56) | 1.34 | (0.71,2.51) |
| p value for trend | 0.11 | 0.46 | ||
| parental smoking | ||||
| none | 1 | 1 | ||
| dad only | 1.00 | (0.74,1.36) | 1.16 | (0.78,1.72) |
| mom only | 0.88 | (0.21,3.78) | 0.71 | (0.09,5.34) |
| both | 2.01 | (1.00,4.02) | 1.17 | (0.36,3.87) |
Models are adjusted for age, sex, parental education, parental history of asthma, parental history of atopy, gestational age, and community.
† Early-onset: asthma diagnosed ≦ 5 yr of age.
‡ Late-onset: asthma diagnosed > 5 yr of age.
*Average cigarettes per day
** Percent of ETS exposure in lifetime