RR (95% CI) of COPD by quartiles of cumulative organic dust exposure
| Exposure category | Overall | Men | Women | ||||||||||
| COPD cases (n) | RR crude | 95% CI | RR adj* | 95% CI | RR crude | 95% CI | RR adj† | 95% CI | RR crude | 95% CI | RR adj† | 95% CI | |
| Cumulative organic dust exposure n=1 75 409 (2 716 631py) | |||||||||||||
| Low (0.02–1.32 mg/m3-year) | 966 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | ||||||
| Intermediate-low (>1.32–3.82 mg/m3-year) | 853 | 0.88 | (0.81 to 0.97) | 0.90 | (0.82 to 0.99) | 0.92 | (0.83 to 1.03) | 0.93 | (0.84 to 1.04) | 0.80 | (0.67 to 0.95) | 0.81 | (0.68 to 0.97) |
| Intermediate-high (>3.82–10.45 mg/m3-year) | 738 | 0.76 | (0.69 to 0.84) | 0.76 | (0.69 to 0.84) | 0.76 | (0.68 to 0.85) | 0.75 | (0.67 to 0.84) | 0.81 | (0.68 to 0.98) | 0.78 | (0.65 to 0.94) |
| High (>10.45–193.9 mg/m3-year) | 605 | 0.63 | (0.57 to 0.69) | 0.52 | (0.47 to 0.58) | 0.63 | (0.57 to 0.71) | 0.51 | (0.46 to 0.58) | 0.73 | (0.57 to 0.95) | 0.58 | (0.45 to 0.75) |
| Per mg/m3-year ‡ | 0.99 | (0.99 to 0.99) | 0.98 | (0.98 to 0.98) | 0.99 | (0.99 to 0.99) | 0.98 | (0.98 to 0.98) | 0.99 | (0.98 to 1.00) | 0.98 | (0.97 to 0.99) | |
| Cumulative organic dust exposure lagged 10 years n=175 409 (2716 631 py) | |||||||||||||
| Low ((0–0.40 mg/m3-year) | 599 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | ||||||
| Intermediate-low (0.40–2.56 mg/m3-year) | 1006 | 1.66 | (1.51 to 1.85) | 1.05 | (0.94 to 1.16) | 1.67 | (1.48 to 1.88) | 1.02 | (0.90 to 1.16) | 1.70 | (1.41 to 2.05) | 1.11 | (0.92 to 1.34) |
| Intermediate-high (>2.56–7.78 mg/m3-year) | 852 | 1.42 | (1.28 to 1.57) | 0.92 | (0.83 to 1.02) | 1.45 | (1.28 to 1.64) | 0.91 | (0.81 to 1.06) | 1.37 | (1.12 to 1.67) | 0.93 | (0.76 to 1.14) |
| High (>7.78–172.69 mg/m3-year) | 705 | 1.17 | (1.05 to 1.31) | 0.63 | (0.56 to 0.70) | 1.20 | (1.06 to 1.36) | 0.61 | (0.53 to 0.69) | 1.33 | (1.03 to 1.70) | 0.72 | (0.56 to 0.93) |
| Per mg/m3-year ‡ | 1.00 | (0.99 to 1.00) | 0.98 | (0.98 to 0.99) | 1.00 | (0.99 to 1.00) | 0.98 | (0.98 to 0.99) | 1.01 | (1.00 to 1.02) | 0.98 | (0.97 to 1.00) | |
| Inception population Cumulative organic dust exposure n=35 957 (411 690 py) | |||||||||||||
| Low (0.02–0.41 mg/m3-year) | 152 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | ||||||
| Intermediate-low (>0.41–0.99 mg/m3-year) | 151 | 0.99 | (0.79 to 1.24) | 1.01 | (0.81 to 1.27) | 0.93 | (0.71 to 1.22) | 0.96 | (0.73 to 1.25) | 1.15 | (0.76 to 1.75) | 1.16 | (0.77 to 1.77) |
| Intermediate-high (>0.99–2.57 mg/m3-year) | 111 | 0.73 | (0.57 to 0.93) | 0.73 | (0.57 to 0.93) | 0.72 | (0.54 to 0.96) | 0.72 | (0.54 to 0.96) | 0.76 | (0.48 to 1.22) | 0.76 | (0.47 to 1.21) |
| High (>2.57–53.9 mg/m3-year) | 92 | 0.60 | (0.47 to 0.78) | 0.56 | (0.43 to 0.73) | 0.55 | (0.40 to 0.75) | 0.52 | (0.38 to 0.71) | 0.76 | (0.48 to 1.20) | 0.68 | (0.43 to 1.08) |
| Per mg/m3-year ‡ | 0.93 | (0.89 to 0.97) | 0.92 | (0.88 to 0.95) | 0.90 | (0.86 to 0.95) | 0.89 | (0.85 to 0.94) | 0.98 | (0.92 to 1.03) | 0.96 | (0.91 to 1.02) | |
| Inception population Cumulative organic dust exposure lagged 5 years n=35 957 (411 690 py) | |||||||||||||
| No exposure (0 mg/m3-year) | 121 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | ||||||
| Low (>0.02–0.55 mg/m3-year) | 156 | 2.06 | (1.62 to 2.61) | 1.29 | (0.98 to 1.70) | 2.33 | (1.75 to 3.10) | 1.42 | (1.02 to 1.97) | 1.53 | (0.99 to 2.36) | 1.03 | (0.62 to 1.72) |
| Intermediate-low (>0.55–1.7 mg/m3-year) | 129 | 1.70 | (1.33 to 2.18) | 1.08 | (0.81 to 1.43) | 1.85 | (1.37 to 2.49) | 1.14 | (0.81 to 1.61) | 1.40 | (0.90 to 2.20) | 0.94 | (0.56 to 1.58) |
| High (>1.7–53.9 mg/m3-year) | 100 | 1.32 | (1.01 to 1.72) | 0.77 | (0.57 to 1.05) | 1.33 | (0.96 to 1.84) | 0.77 | (0.53 to 1.12) | 1.29 | (0.82 to 2.03) | 0.78 | (0.46 to 1.33) |
| Per mg/m3-year ‡ | 0.97 | (0.94 to 1.01) | 0.92 | (0.87 to 0.96) | 0.95 | (0.91 to 1.01) | 0.89 | (0.83 to 0.95) | 1.01 | (0.95 to 1.07) | 0.96 | (0.90 to 1.04) | |
*Adjustment for age group, calendar year and sex.
†Adjustment for age group and calendar year.
‡Continuous cumulative organic dust exposure.
COPD, chronic obstructive pulmonary disease; py, person years.