Odds ratios for parent reported severe wheeze (>10 attacks in past year) in current wheezing children in relation to traffic activity near the child's school
| TAI (in millions) | Wheezers (n) |
>10 Attacks (n (%)) | OR3-150 (95% CI) | Adjusted OR3-151 (95% CI) |
| Primary | n=2648 | n=2331 | ||
| Continuous TAI | p=0.17 | p=0.19 | ||
| Per 10 unit increase | 2648 | 404 (15.3) | 1.03 (0.99 to 1.08) | 1.03 (0.98 to 1.08) |
| Tertiles | p=0.61 | p=0.69 | ||
| Low ⩽21 | 864 | 124 (14.4 ) | 1 | 1 |
| Medium 22–45 | 923 | 142 (15.4) | 1.09 (0.84 to 1.42) | 1.11 (0.84 to 1.47) |
| High >46 | 861 | 138 (16.0) | 1.14 (0.88 to 1.49) | 1.12 (0.84 to 1.50) |
| Secondary | n=2799 | n=2636 | ||
| Continuous TAI | p=0.51 | p=0.40 | ||
| Per 10 unit increase | 2799 | 369 (13.2) | 1.01 (0.97 to 1.06) | 1.02 (0.98 to 1.06) |
| Tertiles | p=0.82 | p=0.56 | ||
| Low ⩽22 | 910 | 115 (12.6) | 1 | 1 |
| Medium 23–31 | 1206 | 163 (13.5) | 1.08 (0.83 to 1.39) | 1.15 (0.88 to 1.50) |
| High ⩾32 | 683 | 91 (13.3) | 1.08 (0.80 to 1.45) | 1.12 (0.83 to 1.52) |