Odds ratios and 95% confidence intervals for recurrent wheezing in children exposed both to the upper quartile of NO2 levels and environmental tobacco smoke, compared with double unexposed children; exposure to outdoor NO2
| Exposure to ETS | Below 4th quartile | Above 4th quartile | Exposure to ETS—independent of NO2 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cases | Controls | OR* | 95% CI | Cases | Controls | OR* | 95% CI | Cases | Controls | OR* | 95% CI | |
| *Adjusted for gender, heredity, maternal age and smoking during pregnancy, breast feeding, and building age. | ||||||||||||
| Not exposed | 87 | 184 | 1 | 30 | 67 | 1.58 | 0.84 to 2.96 | 117 | 251 | 1 | ||
| Exposed | 38 | 63 | 1.08 | 0.58 to 2.02 | 13 | 15 | 3.60 | 1.37 to 9.45 | 51 | 78 | 1.31 | 0.74 to 2.30 |
| Exposure to NO2—independent of ETS | 125 | 247 | 1 | 43 | 82 | 1.86 | 1.0 to 3.34 | |||||