Background
Methods
Study area &sampling
Geocoding
Exposure assessment
-
Residential address.
-
Workplace address.
-
Daily activities
Outcome measures
Statistical analyses
The 1st survey (2004) | Non-cases stratified on exposure | The 2nd survey (2005) | Non-cases stratified on exposure | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Cases | Non-cases | Cases | Non-cases | ||||||||
n (%) | n (%) | OR | NOx <19 | NOx >19 | n (%) | n (%) | OR | NOx <19 μ/m3
| NOx <19 μ/m3
| ||
Sex
| Male | 865 (40.4) | 8726 (45.4) | 1.0 | 7876 (45.5) | 850 (44.9) | 272 (39.0) | 843 (39.0) | 1.0 | 764 (39.3) | 79 (36.6) |
Female | 1275 (59.6) | 10494 (54.6) | 1.2 (1.1-1.3) | 9449 (54.5) | 1045 (55.1) | 426 (61.0) | 1317 (61.0) | 1.0 (0.84-1.2) | 1180 (60.7) | 137 (63.4) | |
Age
| 18-24 | 282 (13.2) | 2119 (11.0) | 1.0 | 1867(10.8) | 252 (13.3) | 69 (9.9) | 216 (10.0) | 1.0 | 186 (9.6) | 30 (13.9) |
(5 Groups)
| 25-34 | 454 (21.2) | 3521 (18.3) | 0.97 (0.83-1.1) | 2937 (17.0) | 584 (30.8) | 142 (20.3) | 435 (20.1) | 1.0 (0.73-1.4) | 364 (18.7) | 71 (32.9) |
35-44 | 395 (18.5) | 4341 (22.6) | 0.68 (0.58-0.80) | 3980 (23.0) | 361 (19.1) | 139 (19.9) | 470 (21.8) | 0.93 (0.67-1.3) | 436 (22.4) | 34 (15.7) | |
45-54 | 460 (21.5) | 4276 (22.2) | 0.81 (0.69-0.95) | 3937 (22.7) | 339 (17.9) | 154 (22.1) | 461 (21.3) | 1.0 (0.75-1.5) | 419 (21.6) | 42 (19.4) | |
55-65 | 549 (25.7) | 4963 (25.8) | 0.83 (0.71-0.97) | 4604 (26.6) | 359 (18.9) | 194 (27.8) | 578 (26.8) | 1.1 (0.77-1.4) | 539 (27.7) | 39 (18.1) | |
Smoking
| No | 1630 (76.6) | 14890 (77.9) | 1.0 | 13556 (78.6) | 1334 (70.7) | 530 (76.3) | 1690 (78.6) | 1.0 | 1534 (79.2) | 156 (72.6) |
Yes, sometimes | 131 (6.2) | 984 (5.1) | 1.0 (0.92-1.2) | 836 (4.8) | 148 (7.8) | 34 (4.9) | 99 (4.6) | 1.2(0.92-1.4) | 84 (4.3) | 15 (7.0) | |
Daily | 367 (17.2) | 3250 (17.0) | 1.2 (1.0-1.5) | 2846 (16.5) | 404 (21.4) | 131 (18.8) | 362 (16.8) | 1.1(0.73-1.6) | 318 (16.4) | 44 (20.5) | |
BMI
| < 25 | 1001 (48.4) | 10325 (55.0) | 1.0 | 9228 (54.5) | 1097 (59.3) | 315 (46.3) | 1193 (56.2) | 1.0 | 1066 (55.7) | 127 (60.8) |
Overweight | 740 (35.8) | 6399 (34.1) | 1.2 (1.1-1.3) | 5821 (34.4) | 578 (31.2) | 264 (38.8) | 676 (31.9) | 1.5 (1.2-1.8) | 614 (32.1) | 62 (29.7) | |
Fat | 327 (15.8) | 2057 (11.0) | 1.6 (1.4-1.9) | 1881 (11.1) | 176 (9.5) | 102 (15.0) | 253 (11.9) | 1.5 (1.2-2.0) | 233 (12.2) | 20 (9.6) | |
SEI
| Professionals, etc | 234 (11.8) | 2333(12.9) | 1.0 | 2132 (13.1) | 201 (11.3) | 81 (12.6) | 307(14.9) | 1.0 | 278 (15.0) | 29 (14.3) |
Intermediate non-manual | 340 (17.1) | 3366 (18.7) | 1.0 (0.85-1.2) | 3086 (19.0) | 280 (15.8) | 124 (19.3) | 436(21.2) | 1.1(0.79-1.5) | 399 (21.5) | 37 (18.2) | |
Assistant non-manual | 187 (9.4) | 1735 (9.6) | 1.1 (0.88-1.3) | 1559 (9.6) | 176 (9.9) | 71 (11.0) | 188(9.1) | 1.4 (0.99-2.1) | 175 (9.4) | 13 (6.4) | |
Skilled workers | 245 (12.3) | 2359 (13.1) | 1.0 (0.86-1.3) | 2171 (13.3) | 188 (10.6) | 72 (11.2) | 251(12.2) | 1.1(0.76-1.6) | 226 (12.2) | 25 (12.3) | |
Unskilled workers | 334 (16.8) | 3150 (17.5) | 1.1 (0.89-1.3) | 2854 (17.5) | 296 (16.7) | 100 (15.5) | 287(13.9) | 1.3 (0.95-1.8) | 252 (13.6) | 35 (17.2) | |
Self-employed (non-prof.) | 107 (5.4) | 1275 (7.1) | 0.8 (0.66-1.1) | 1177 (7.2) | 98 (5.5) | 38 (5.9) | 155(7.5) | 0.93 (0.60-1.4) | 145 (7.8) | 10 (4.9) | |
Disability pensioners | 192 (9.7) | 1042 (5.8) | 1.8 (1.5-2.3) | 927 (5.7) | 115 (6.5) | 66(10.2) | 131(6.4) | 1.9(1.3-2.8) | 117 (6.3) | 14 (6.9) | |
Unemployed | 139 (7.0) | 1073 (5.9) | 1.3 (1.0-1.6) | 893 (5.5) | 180 (10.2) | 32(5.0) | 107(5.2) | 1.1 (0.71-1.8) | 91 (4.9) | 16 (7.9) | |
Students | 210 (10.6) | 1702 (9.4) | 1.2 (1.0-1.5) | 1464 (9.0) | 238 (13.4) | 60(9.3) | 197(9.6) | 1.2(0.79-1.7) | 173 (9.3) | 24 (11.8) | |
Exposure to | |||||||||||
chemicals, dust, or fumes at work | Never | 909 (61.7) | 8876 (62.7) | 1.0 | 8054 (62.4) | 91 (62.3) | 333 (65.7) | 1085 (66.9) | 1.0 | 988 (67.1) | 97 (65.1) |
More seldom | 303 (20.6) | 2731 (19.3) | 1.0 (0.86-1.2) | 2511 (19.5) | 30 (20.5) | 101 (19.9) | 282 (17.4) | 0.97 (0.68-1.4) | 256 (17.4) | 26 (17.4) | |
Few days/week | 94 (6.4) | 946 (6.7) | 0.97 (0.78.-1.2) | 872 (6.8) | 8 (5.5) | 28 (5.5) | 103 (6.4) | 0.89 (0.57-1.4) | 91 (6.2) | 12 (8.1) | |
Every day | 168 (11.4) | 1597 (11.3) | 1.1 (0.95-1.2) | 1468 (11.4) | 17 (11.6) | 45 (8.9) | 152 (9.4) | 1.2 (0.90-1.5) | 138 (9.4) | 14 (9.4) |
Results
Description of study population, selection, and exposure
The 2nd survey | NOx at workplace address (μg/m3) | Time outdoor in traffic/day (self-reported) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
total | 0-8 | 8-11 | 11-14 | 14-19 | > 19 | Total | 0-30 min | 30-1 h | 1-2 h | > 2 h | ||
NOx at residential address (μg/m3) | 0-8 | 770 | 412(53.5%) | 78(10.1%) | 132(17.1%) | 60(7.8%) | 88(11.4%) | 770 | 159(20.6%) | 306(39.7%) | 188(24.4%) | 117(15.2%) |
8-11 | 210 | 30(14.3%) | 44(21.0%) | 59(28.1%) | 32(15.2%) | 45(21.4%) | 210 | 34(16.2%) | 87(41.4%) | 55(26.2%) | 34(16.2%) | |
11-14 | 210 | 13(6.2%) | 15(7.1%) | 102(48.6%) | 26(12.4%) | 54(25.7%) | 210 | 41(19.5%) | 88(41.9%) | 65(31.0%) | 16(7.6%) | |
14-19 | 161 | 4(2.5%) | 7(4.3%) | 38(23.6%) | 39(24.2%) | 73(45.3%) | 161 | 29(18.0%) | 65(40.4%) | 41(25.5%) | 26(16.1%) | |
> 19 | 137 | 9(6.6%) | 4(2.9%) | 18(13.1%) | 26(19.0%) | 80(58.4%) | 137 | 20(14.6%) | 53(38.7%) | 37(27.0%) | 27(19.7%) |
Asthma medication | ||||||
---|---|---|---|---|---|---|
No | Yes, when needed | Yes, regularly | Total | |||
Asthmatic symptoms | NO | Count | 2253 | 81 | 45 | 2379 |
% | 94.7% | 3.4% | 1.9% | 100.0% | ||
YES | Count | 68 | 185 | 200 | 453 | |
% | 15.0% | 40.8% | 44.2% | 100.0% |
Residential traffic
The 1st survey (2004) | The 2nd survey (2005) | ||||||||
---|---|---|---|---|---|---|---|---|---|
Residential Address | n | Asthma n (%) | Asthma (OR)1
| n | Asthma n (%) | Asthma (OR)1
| Asthma symptoms n (%) | Asthma symtoms (OR)1
| |
Self-report Heaviest road <50 m | 0-1 cars/min | - | - | - | 445 | 105 (23.6) | 1.0 | 71(16.0) | 1.0 |
< 2 cars/min | - | - | - | 1512 | 339 (22.4) | 1.10 (0.81-1.5) | 216(14.4) | 0.95 (0.66-1.4) | |
2-5 cars/min | - | - | - | 410 | 113 (27.6) | 1.17 (0.80-1.7) | 81(19.9) | 1.2 (0.76-1.8) | |
6-10 cars/min | - | - | - | 203 | 56 (27.6) | 1.20 (0.74-2.0) | 34(17.0) | 0.79 (0.42-1.5) | |
> 10 cars/min | - | - | - | 258 | 76 (29.5) | 1.5 (0.94-2.3) | 48(18.5) | 1.2 (0.72-2.1) | |
GIS Heaviest road <50 m | no heavy road | 15584 | 1542 (9.9) | 1.0 | 2100 | 494 (23.5) | 1.0 | 316 (15.1) | 1.0 |
< 2 cars/min | 3691 | 375 (10.2) | 1.0 (0.90-1.2) | 472 | 121 (25.6) | 1.2 (0.89-1.6) | 79 (16.8) | 1.1 (0.81-1.6) | |
2-5 cars/min | 1555 | 159 (10.2) | 0.95 (0.76-1.2) | 216 | 61 (28.2) | 1.2 (0.79-1.7) | 39 (18.1) | 1.1 (0.71-1.8) | |
6-10 cars/min | 307 | 35 (11.4) | 1.0 (0.65-1.6) | 34 | 10 (29.4) | 1.0 (0.33-3.2) | 7(20.6) | 1.4 (0.39-5.1) | |
> 10 cars/min | 223 | 29 (13.0) | 1.8 (1.1-2.8) | 36 | 12 (33.3) | 2.3 (0.99-5.2) | 12 (33.3) | 4.6 (2.0-10.6) | |
GIS Heaviest road <100 m | no heavy road | 10875 | 1062 (9.8) | 1.0 | 1461 | 330 (22.6) | 1.0 | 215 (14.7) | 1.0 |
< 2 cars/min | 5741 | 589 (10.3) | 1.1 (0.92-1.2) | 744 | 197 (26.5) | 1.4 (1.1-1.7) | 128 (17.4) | 1.2 (0.92-1.7) | |
2-5 cars/min | 3309 | 327 (9.9) | 0.96 (0.81-1.1) | 462 | 121 (26.2) | 1.2 (0.88-1.6) | 75 (16.3) | 1.1 (0.80-1.7) | |
6-10 cars/min | 894 | 101 (11.3) | 1.2 (0.92-1.6) | 119 | 29 (24.4) | 1.4 (0.82-2.3) | 14 (11.8) | 0.81 (0.38-1.7) | |
> 10 cars/min | 541 | 61 (11.3) | 1.3 (0.95-1.8) | 72 | 21 (29.2) | 1.6 (0.82-3.2) | 21 (29.2) | 2.7 (1.3-5.5) | |
GIS Heaviest road <250 m | no heavy road | 4412 | 429 (9.7) | 1.0 | 590 | 136 (23.1) | 1.0 | 84 (14.2) | 1.0 |
< 2 cars/min | 7079 | 698 (9.9) | 1.0 (0.86-1.2) | 904 | 225 (24.9) | 1.1 (0.85-1.5) | 147 (16.4) | 1.1 (0.7-1.5) | |
2-5 cars/min | 6297 | 636 (10.1) | 0.96 (0.82-1.1) | 870 | 220 (25.3) | 1.1 (0.83-1.5) | 139 (16.1) | 1.0 (0.7-1.4) | |
6-10 cars/min | 2100 | 222 (10.6) | 1.1 (0.86-1.3) | 298 | 68 (22.8) | 1.2 (0.77-1.7) | 42 (14.1) | 1.0 (0.6-1.9) | |
> 10 cars/min | 1472 | 155 (10.5) | 0.98 (0.76-1.3) | 196 | 49 (25.0) | 0.8 (0.51-1.4) | 41 (20.7) | 1.1 (0.6-1.9) | |
GIS NOx (μg/m3 ) (250 × 250 m) | 0-8 | 11273 | 1111 (9.9) | 1.0 | 1508 | 376 (24.9) | 1.0 | 240 (16.0) | 1.0 |
8-11 | 3133 | 300 (9.6) | 0.94 (0.79-1.1) | 371 | 78 (21.0) | 0.79 (0.56-1.1) | 45 (12.3) | 1.0 (0.74-1.49) | |
11-14 | 2496 | 256 (10.3) | 1.1 (0.93-1.3) | 388 | 90 (23.2) | 1.2 (0.86-1.6) | 57 (14.8) | 0.97 (0.68-1.39) | |
14-19 | 2319 | 229 (9.9) | 0.84 (0.69-1.0) | 298 | 77 (25.8) | 1.0 (0.73-1.5) | 55 (18.4) | 0.99 (0.60-1.6) | |
> 19 | 2139 | 244 (11.4) | 1.1 (0.93-1.4) | 293 | 77 (26.3) | 1.1 (077) | 56 (19.1) | 1.1 (0.60-1.9) |
Traffic exposure at workplace address
The 2ndsurvey | ||||||
---|---|---|---|---|---|---|
WORKPLACE ADDRESS | n | Asthma n (%) | Asthma (OR)1
| Asthma Symptoms. n (%) | Asthma Symptoms (OR)1
| |
Self-reported Heaviest road <50 m | 0-1 cars/min | 601 | 144 (24.0) | 1.0 | 80 (13.4) | 1.0 |
2-5 cars/min | 571 | 132 (23.1) | 1.1 (0.80-1.5) | 79 (14.0) | 0.95 (0.66-1.4) | |
6-10 cars/min | 351 | 75 (21.4) | 1.2 (0.79-1.7) | 49 (14.0) | 1.2 (0.76-1.8) | |
> 10 cars/min | 606 | 147 (24.3) | 1.2 (0.73-1.9) | 96 (15.9) | 0.79 (0.42-1.5) | |
Workplace varies | 214 | 50 (23.4) | 1.5 (0.93-2.7) | 34 (16.0) | 1.2 (0.72-2.1) | |
GIS Heaviest road <50 m | no heavy road | 161 | 36 (22.4) | 1.0 | 21 (13.2) | 1.0 |
< 2 cars/min | 267 | 61 (22.8) | 1.0 (0.62-1.7) | 34 (12.7) | 1.1 (0.55-2.1) | |
2-5 cars/min | 673 | 149 (22.1) | 0.91 (0.57-1.4) | 94 (14.0) | 1.2 (0.65-2.1) | |
6-10 cars/min | 407 | 83 (20.4) | 0.92 (0.56-1.5) | 45 (11.1) | 1.1 (0.58-2.0) | |
> 10 cars/min | 326 | 78 (23.9) | 1.0 (0.62-1.7) | 51 (15.7) | 1.4 (0.72-2.6) | |
GIS Heaviest road <100 m | no heavy road | 527 | 126 (23.9) | 1.0 | 74 (14.1) | 1.0 |
< 2 cars/min | 327 | 76 (23.2) | 0.88 (0.61-1.3) | 41 (12.5) | 0.79 (0.49-1.3) | |
2-5 cars/min | 509 | 102 (20.0) | 0.85 (0.61-1.2) | 67 (13.2) | 0.97 (0.65-1.5) | |
6-10 cars/min | 277 | 58 (20.9) | 0.98 (0.66-1.5) | 35 (12.7) | 1.2 (0.74-1.9) | |
> 10 cars/min | 194 | 45 (23.2) | 0.99 (0.63-1.5) | 28 (14.5) | 1.2 (0.72-2.1) | |
GIS Heaviest road <250 m | no heavy road | 161 | 36 (22.4) | 1.0 | 21 (13.2) | 1.0 |
< 2 cars/min | 267 | 61 (22.8) | 1.0 (0.62-1.8) | 34 (12.7) | 1.1 (0.55-2.1) | |
2-5 cars/min | 673 | 149 (22.1) | 0.91 (0.57-1.4) | 94 (14.0) | 1.2 (0.65-2.1) | |
6-10 cars/min | 407 | 83 (20.4) | 0.92 (0.56-1.5) | 45 (11.1) | 1.1 (0.58-2.0) | |
> 10 cars/min | 326 | 78 (23.9) | 1.0 (0.62-1.7) | 51 (15.7) | 1.4 (0.72-2.6) | |
GIS NOx (μg/m3) (250 × 250 m) | 0-8 | 558 | 129 (23.1) | 1.0 | 70 (12.6) | 1.0 |
8-11 | 163 | 34 (20.9) | 0.88 (0.55-1.4) | 23 (14.1) | 1.1 (0.65-2.0) | |
11-14 | 455 | 94 (20.7) | 0.91 (0.65-1.3) | 56 (12.4) | 0.99 (0.64-1.5) | |
14-19 | 227 | 48 (21.1) | 1.0 (0.68-1.5) | 27 (11.9) | 1.2 (0.71-2.0) | |
> 19 | 431 | 102 (23.7) | 0.98 (0.70-1.4) | 69 (16.1) | 1.3 (0.88-2.0) | |
DAILY ACTIVITIES
|
n
|
Asthma n (%)
|
Asthma (OR)
1
|
Asthma symptoms n (%)
|
Asthma Symptoms n (%)
| |
Time outdoor in traffic/day | 0-30 min | 622 | 134 (21.5) | 1.0 | 79 (12.8) | 1.0 |
30 min-1 h | 1066 | 248 (23.3) | 1.1 (0.8-1.4) | 159 (15.1) | 1.2 (0.83-1.7) | |
1-2 h | 715 | 194 (27.1) | 1.1 (0.8-1.5) | 121 (17.0) | 1.4 (0.91-2.0) | |
> 2 h | 453 | 121 (26.7) | 1.0 (0.7-1.4) | 92 (20.4) | 1.3 (0.83-2.0) | |
Commuting time to work | < 15 min | 881 | 211 (24.0) | 1.0 | 117 (13.4) | 1.0 |
15-30 min | 915 | 207 (22.6) | 0.90 (0.70-1.1) | 140 (15.4) | 1.1 (0.84-1.5) | |
30 min-1 h | 408 | 99 (24.3) | 1.0 (0.73-1.4) | 60 (14.8) | 1.2 (0.78-1.7) | |
> 1 h | 129 | 29 (22.5) | 0.77 (0.45-1.33) | 18 (14.2) | 0.92 (0.47-1.8) |
Traffic exposure during daily activities
Accounting for total traffic exposure
The 2ndsurvey | ||||||
---|---|---|---|---|---|---|
COMBINED EXPOSURE | n | Asthma, n (%) | Asthma, n (%) | Asthma OR1
| Asthma symptoms, n (%) | Asthma symptoms (OR)1
|
Total exposure2 C = 30
| 1st
| 298 | 72(24.2%) | 1.00 | 41(13.8%) | 1.00 |
2nd
| 298 | 68(22.8%) | 0.90 (0.61-1.35) | 32(10.8%) | 0.70(0.41-1.18) | |
3rd
| 297 | 59(19.9%) | 0.76 (0.51-1.15) | 43(14.5%) | 1.09(0.67-1.77) | |
4th
| 298 | 65(21.8%) | 0.87 (0.58-1.31) | 41(13.8%) | 1.09(0.66-1.79) | |
5th
| 297 | 70(23.6%) | 0.96 (0.64-1.44) | 48(16.2%) | 1.28(0.79-2.08) | |
Total exposure2 C = 300
| 1st
| 298 | 67(22.5%) | 1.00 | 35(11.8%) | 1.00 |
2nd
| 298 | 67/22.5%) | 1.02 (0.68-1.53) | 35(11.8%) | 1.06(0.63-1.79) | |
3rd
| 297 | 69(23.2%) | 1.00 (0.66-1.50) | 48(16.2%) | 1.50(0.91-2.48) | |
4th
| 298 | 65(21.8%) | 0.88 (0.58-1.34) | 45(15.2%) | 1.33(0.79-2.21) | |
5th
| 297 | 66(22.2%) | 0.88 (0.58-1.33) | 42(14.1%) | 1.18(0.71-1.99) | |
Residential + workplace Address2
| 1st
| 298 | 73(24.5%) | 1.00 | 41(13.8%) | 1.00 |
2nd
| 298 | 69(23.2%) | 0.91 (0.61-1.35) | 36(12.1%) | 0.89(0.53-1.47) | |
3rd
| 297 | 54(18.2%) | 0.64 (0.42-0.97) | 36(12.2%) | 0.87(0.52-1.44) | |
4th
| 298 | 69(23.2%) | 0.98 (0.66-1.46) | 46(15.5%) | 1.31(0.81-2.12) | |
5th
| 297 | 69(23.2%) | 0.94 (0.63-1.41) | 46(15.5%) | 1.27(0.78-2.07) | |
Workplace Address | 1st
| 298 | 74(24.8%) | 1.00 | 40(13.5%) | 1.00 |
2nd
| 298 | 64(21.5%) | 0.81 (0.54-1.22) | 41(13.8%) | 1.12(0.68-1.85) | |
3rd
| 297 | 66(22.2%) | 0.87 (0.58-1.31) | 41(13.8%) | 1.11(0.67-1.85) | |
4th
| 298 | 67/22.5%) | 0.92 (0.62-1.37) | 40(13.5%) | 1.14(0.70-1.88) | |
5th
| 297 | 63(21.2%) | 0.77 (0.51-1.16) | 43(14.6%) | 1.19(0.72-1.96) | |
Residential Address | 1st
| 298 | 71(23.8%) | 1.00 | 41(13.8%) | 1.00 |
2nd
| 298 | 70(23.5%) | 0.90 (0.60-1.34) | 35(11.8%) | 0.80(0.48-1.33) | |
3rd
| 297 | 58(19.5%) | 0.78 (0.52-1.18) | 41(13.9%) | 1.08(0.66-1.75) | |
4th
| 298 | 66(22.1%) | 0.91 (0.60-1.36) | 40(13.4%) | 1.09(0.66-1.80) | |
5th
| 297 | 69(23.2%) | 0.96 (0.64-1.44) | 48(16.2%) | 1.31(0.81-2.13) |