Odds ratios and 95% confidence intervals for recurrent wheezing in children up to the age of 2, in the BAMSE case-control study, in relation to measured and calculated annual outdoor and indoor NO2 exposure
| Controls | Cases | Concentration of NO2 (µg/m3) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| <25th centile | 25–50th centile | 51–75th centile | >75th centile | ||||||
| OR | OR* | 95% CI | OR* | 95% CI | OR* | 95% CI | |||
| *Adjusted for gender, heredity, maternal age and smoking, any breast feeding, and building age. | |||||||||
| †Indoor NO2 exposure, range within different quartiles: <8.4 µg/m3; 8.4–11.6 µg/m3; 11.7–15.6 µg/m3; and >15.6 µg/m3, respectively. | |||||||||
| ‡Outdoor NO2 exposure, range within different quartiles: <14.8 µg/m3; 14.8–21.3 µg/m3; 21.4–28.4 µg/m3; and >28.4 µg/m3, respectively. | |||||||||
| Indoor exposure† | |||||||||
| Based on measurements: | |||||||||
| In quartiles | 330 | 170 | 1 | 0.96 | 0.52 to 1.77 | 1.08 | 0.57 to 2.03 | 1.51 | 0.81 to 2.82 |
| Exposed to >75th centile v lower | 1 | 1.48 | 0.91 to 2.42 | ||||||
| Outdoor exposure‡ | |||||||||
| Based on measurements: | |||||||||
| In quartiles | 332 | 168 | 1 | 0.76 | 0.42 to 1.36 | 0.80 | 0.43 to 1.47 | 1.60 | 0.78 to 3.26 |
| Exposed to >75th centile v lower | 1 | 1.92 | 1.05 to 3.53 | ||||||
| Based on calculated annual average exposure: | |||||||||
| In quartiles | 332 | 171 | 1 | 0.73 | 0.41 to 1.31 | 0.71 | 0.38 to 1.34 | 1.74 | 0.87 to 3.49 |
| Exposed to >75th centile v lower | 1 | 1.92 | 1.05 to 3.53 | ||||||