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 indoor 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 | 90 | 188 | 1 | 28 | 63 | 1.09 | 0.62 to 1.91 | 118 | 251 | 1 | ||
| Exposed | 33 | 63 | 0.96 | 0.51 to 1.83 | 19 | 15 | 3.10 | 1.32 to 7.30 | 52 | 78 | 1.31 | 0.75 to 2.30 |
| Exposure to NO2—independent of ETS | 123 | 251 | 1 | 47 | 78 | 1.47 | 0.91 to 2.37 | |||||