Table 1. Characteristics of the study population according to self-reported traffic, distance from high traffic roads (HTRs), metres of HTRs within 200 m from home, particulate matter (PM) emissions, and estimated nitrogen dioxide (NO2) from the land-use regression model.
| n | % | Self-reported intense traffic (%) | Distance from HTR, mean (SD) | Metres of HTR within 200 m from home, mean (SD) | PM emissions (kg/m2), mean (SD) | Estimated NO2 (μg/m3), mean (SD) | |
| Gender | |||||||
| Males | 4491 | 47.3 | 15.0 | 464 (531) | 684 (474) | 0.120 (0.081) | 45.3 (8) |
| Females | 4997 | 52.7 | 15.0 | 463 (536) | 684 (466) | 0.120 (0.081) | 45.5 (8) |
| p Value | 0.891 | 0.870 | 0.958 | 0.448 | 0.043 | ||
| Age (years) | |||||||
| 25–34 | 1722 | 18.2 | 12.2 | 598 (610) | 677 (411) | 0.098 (0.080) | 43.2 (8) |
| 35–44 | 5539 | 58.4 | 15.2 | 452 (535) | 668 (470) | 0.121 (0.080) | 45.4 (8) |
| 45+ | 2228 | 23.5 | 16.4 | 389 (438) | 723 (491) | 0.136 (0.082) | 47.0 (8) |
| p | 0.003 | <0.001 | 0.037 | <0.001 | <0.001 | ||
| Education (years) | |||||||
| <9 | 4282 | 45.1 | 11.6 | 559 (623) | 688 (462) | 0.106 (0.079) | 43.6 (8) |
| 9–13 | 3690 | 38.9 | 17.2 | 414 (453) | 699 (477) | 0.126 (0.082) | 46.2 (8) |
| >13 | 1356 | 14.3 | 19.5 | 292 (328) | 641 (463) | 0.148 (0.076) | 49.1 (7) |
| p trend | <0.001 | <0.001 | 0.153 | <0.001 | <0.001 | ||
| Occupation | |||||||
| Managerial/professional | 1112 | 11.7 | 18.2 | 349 (395) | 628 (454) | 0.132 (0.079) | 47.3 (8) |
| Other non-manual | 3785 | 39.9 | 16.9 | 418 (484) | 700 (482) | 0.130 (0.082) | 46.4 (8) |
| Manual labour | 1248 | 13.2 | 13.3 | 543 (594) | 690 (466) | 0.109 (0.079) | 44.1 (8) |
| Other or unemployed | 1147 | 12.1 | 12.2 | 498 (547) | 650 (434) | 0.111 (0.080) | 44.3 (8) |
| Housewife | 2091 | 22.0 | 12.2 | 534 (605) | 702 (471) | 0.108 (0.081) | 43.9 (8) |
| p trend* | <0.001 | <0.001 | 0.750 | <0.001 | <0.001 | ||
| Area-based SEP | |||||||
| High | 1698 | 17.9 | 19.6 | 272 (261) | 649 (495) | 0.157 (0.076) | 50.3 (6) |
| Medium high | 1688 | 17.8 | 21.0 | 310 (361) | 748 (512) | 0.147 (0.081) | 48.2 (8) |
| Intermediate | 1657 | 17.5 | 19.9 | 398 (483) | 689 (459) | 0.136 (0.082) | 46.4 (8) |
| Medium low | 1824 | 19.2 | 11.4 | 511 (549) | 683 (414) | 0.098 (0.076) | 42.4 (8) |
| Low | 2432 | 25.6 | 7.1 | 709 (669) | 589 (388) | 0.083 (0.066) | 41.6 (7) |
| p trend | <0.001 | <0.001 | 0.144 | <0.001 | <0.001 | ||
| Smoking habit | |||||||
| Non-smoker | 2977 | 31.4 | 14.8 | 440 (504) | 688 (474) | 0.121 (0.083) | 45.4 (8) |
| Ex-smoker | 2641 | 27.8 | 15.8 | 462 (548) | 683 (465) | 0.120 (0.080) | 45.7 (8) |
| Current smoker | 3822 | 40.3 | 14.2 | 481 (545) | 682 (469) | 0.119 (0.081) | 45.2 (8) |
| p trend | 0.478 | 0.006 | 0.784 | 0.251 | 0.194 | ||
| Humidity or moulds | |||||||
| No | 9010 | 95.0 | 15.0 | 460 (530) | 684 (468) | 0.121 (0.081) | 45.5 (8) |
| Yes | 411 | 4.3 | 13.1 | 551 (581) | 698 (511) | 0.100 (0.079) | 43.0 (8) |
| p Value | 0.451 | 0.023 | 0.820 | <0.001 | 0.936 | ||
| Chronic bronchitis or emphysema | |||||||
| No | 9091 | 95.8 | 14.9 | 463 (535) | 683 (470) | 0.120 (0.081) | 45.4 (8) |
| Yes | 397 | 4.2 | 17.5 | 466 (492) | 712 (468) | 0.119 (0.077) | 45.3 (8) |
| p Value | 0.183 | 0.919 | 0.491 | 0.858 | 0.818 | ||
| Asthma | |||||||
| No | 9016 | 95.0 | 14.8 | 465 (537) | 685 (469) | 0.120 (0.081) | 45.4 (8) |
| Yes | 472 | 5.0 | 19.1 | 442 (463) | 659 (472) | 0.121 (0.081) | 45.7 (8) |
| p Value | 0.016 | 0.347 | 0.490 | 0.866 | 0.379 | ||
| Rhinitis | |||||||
| No | 8261 | 87.1 | 14.7 | 468 (539) | 681 (465) | 0.119 (0.081) | 45.3 (8) |
| Yes | 1227 | 12.9 | 17.3 | 431 (495) | 701 (499) | 0.127 (0.081) | 46.4 (8) |
| p Value | 0.018 | 0.015 | 0.434 | 0.001 | <0.001 |
SEP, socioeconomic position.Totals may vary because of missing information.
p for testing homogeneity.
*Housewives are excluded.