| Asthma symptoms | Cough or phlegm | ||||||
---|---|---|---|---|---|---|---|---|
 | n cases | (%) | OR* | 95% CI | n cases | (%) | OR* | 95% CI |
Traffic density | Â | Â | Â | Â | Â | Â | Â | Â |
   Absent | 564 | 12.5 | 1.00 |  | 270 | 6.0 | 1.00 |  |
   Low | 1,228 | 12.6 | 1.04 | 0.93–1.16 | 558 | 5.7 | 0.94 | 0.80–1.10 |
   Moderate | 1,375 | 13.8 | 1.13 | 1.01–1.26 | 689 | 6.9 | 1.04 | 0.89–1.22 |
   High | 795 | 14.6 | 1.17 | 1.03–1.33 | 475 | 8.7 | 1.24 | 1.04–1.49 |
Frequency cars transit | Â | Â | Â | Â | Â | Â | Â | Â |
   Never | 309 | 12.7 | 1.00 |  | 142 | 5.9 | 1.00 |  |
   Sometimes | 1,147 | 12.1 | 0.95 | 0.83–1.10 | 517 | 5.5 | 0.90 | 0.74–1.10 |
   Frequently | 1,399 | 13.6 | 1.06 | 0.93–1.22 | 679 | 6.6 | 1.02 | 0.84–1.26 |
   Continuously | 1,108 | 14.9 | 1.16 | 1.00–1.33 | 656 | 8.8 | 1.32 | 1.08–1.63 |
Frequency trucks transit | Â | Â | Â | Â | Â | Â | Â | Â |
   Never | 1,412 | 12.3 | 1.00 |  | 652 | 5.7 | 1.00 |  |
   Sometimes | 1,644 | 13.6 | 1.10 | 1.02–1.19 | 812 | 6.7 | 1.14 | 1.02–1.26 |
   Frequently | 682 | 14.5 | 1.16 | 1.05–1.29 | 399 | 8.5 | 1.41 | 1.23–1.61 |
   Continuously | 211 | 15.7 | 1.27 | 1.08–1.50 | 132 | 9.8 | 1.67 | 1.36–2.06 |