Incident chronic bronchitis and chronic cough at second assessment, per IQR increase in each pollutant
| Adjusted* OR (95% CI) | ||||
| Cases/non-cases (n/n) | PM2.5 | NO2 | Black carbon | |
| All participants | ||||
| Chronic bronchitis | 2946/62 063 | 1.01 (0.96 to 1.06) | 1.07 (1.02 to 1.13) | 1.07 (1.02 to 1.13) |
| Chronic cough | 3956/61 022 | 1.01 (0.96 to 1.05) | 1.03 (0.98 to 1.08) | 1.03 (0.99 to 1.08) |
| Females | ||||
| Chronic bronchitis | 1479/37 205 | 1.03 (0.96 to 1.10) | 1.11 (1.03 to 1.20) | 1.10 (1.02 to 1.17) |
| Chronic cough | 2099/36 563 | 1.03 (0.97 to 1.09) | 1.07 (1.00 to 1.14) | 1.05 (0.99 to 1.12) |
| Age >=50 | ||||
| Chronic bronchitis | 1229/21 619 | 0.97 (0.91 to 1.03) | 1.02 (0.95 to 1.10) | 1.05 (0.98 to 1.12) |
| Chronic cough | 1645/21 186 | 0.99 (0.93 to 1.04) | 1.02 (0.96 to 1.09) | 1.03 (0.97 to 1.09) |
| No post-secondary education | ||||
| Chronic bronchitis | 2233/42 389 | 1.01 (0.96 to 1.07) | 1.08 (1.01 to 1.15) | 1.08 (1.02 to 1.15) |
| Chronic cough | 2996/41 601 | 1.01 (0.97 to 1.06) | 1.04 (0.99 to 1.11) | 1.05 (1.00 to 1.11) |
| Never smokers | ||||
| Chronic bronchitis | 1090/30 452 | 1.04 (0.96 to 1.12) | 1.14 (1.05 to 1.25) | 1.14 (1.06 to 1.23) |
| Chronic cough | 1507/30 021 | 1.04 (0.97 to 1.11) | 1.11 (1.03 to 1.19) | 1.08 (1.01 to 1.16) |
| Asthmatics | ||||
| Chronic bronchitis | 418/4035 | 1.05 (0.92 to 1.20) | 1.09 (0.94 to 1.27) | 1.11 (0.97 to 1.27) |
| Chronic cough | 462/3990 | 0.98 (0.86 to 1.12) | 1.08 (0.93 to 1.25) | 1.06 (0.93 to 1.21) |
Statistically significant results are shown in bold.
*Model adjusted for sex, age, educational attainment (low: junior secondary/lower vocational or less, medium: senior secondary/secondary vocational, high: higher vocational/university), BMI (continuous), smoking status (never, ex, current), pack-years smoking, environmental tobacco smoke at home and follow-up time.
BMI, body mass index; NO2, nitrogen dioxide; PM2.5, particulate matter with a diameter of less than 2.5 µm.