ORs with 95% CIs for current smoking and occupational exposure to VGDF as risk factors for respiratory symptoms
| ER (n=10 004) | ER+LR1 (n=13 127) | ER+LR1+LR2 (n=16 099) | Homogeneity between ER/LR1/LR2(p value) | NR (n=260) | Homogeneity between LR2/NR (p value) | Weighted* (n=16 359) | |
|---|---|---|---|---|---|---|---|
| Current smoking†‡ | |||||||
| Productive cough | 2.78 (2.44 to 3.16) | 2.74 (2.44 to 3.07) | 2.62 (2.36 to 2.90) | 0.439 | 3.37 (1.44 to 7.44) | 0.440 | 2.99 (2.70 to 3.31) |
| Wheezing in the past 12 months | 2.64 (2.35 to 2.96) | 2.61 (2.63 to 2.89) | 2.59 (2.37 to 2.84) | 0.838 | 1.70 (0.83 to 3.47) | 0.293 | 1.95 (1.79 to 2.14) |
| Chronic cough | 1.71 (1.52 to 1.92) | 1.70 (1.53 to 1.88) | 1.59 (1.45 to 1.74) | 0.052 | 2.33 (1.05 to 5.16) | 0.271 | 1.95 (1.78 to 2.15) |
| Occupational exposure to VGDF ever§¶ | |||||||
| Productive cough | 1.59 (1.41 to 1.79) | 1.59 (1.43 to 1.77) | 1.73 (1.57 to 1.91) | 0.003 | 1.29 (0.61 to 2.72) | 0.819 | 1.39 (1.27 to 1.53) |
| Wheezing in the past 12 months | 1.63 (1.47 to 1.82) | 1.63 (1.49 to 1.80) | 1.70 (1.56 to 1.85) | 0.106 | 1.07 (0.56 to 2.01) | 0.229 | 1.21 (1.12 to 1.32) |
| Chronic cough | 1.40 (1.26 to 1.56) | 1.41 (1.29 to 1.55) | 1.47 (1.35 to 1.60) | 0.061 | 1.07 (0.57 to 2.21) | 0.877 | 1.18 (1.08 to 1.29) |
Bold typeface represents p values less than 0.05.
The calculations are based on early responders (ER), responders after the first reminder (ER+LR1), responders after the second reminder (ER+LR1+LR2), among the non-responders (NR), and weighted responses.
*Weighting the 260 non-responders by 42.66 and the 16 099 responders (LR2) by 0.3272, ensuring that the 16 359 responses represent the entire study sample of 50 000.
†Compared to never-smokers.
‡Adjusted for age, sex and area of domicile.
§Compared to those not occupationally exposed to vapour, gas, dust or fumes.
¶Adjusted for age, sex, area of domicile and smoking habits.