Table 2. Bivarite and multivariable models results for the associations between environmental factors and COPD exacerbation hospital admissions for study time periods (1, 1.5, 2 and 3 weeks before hospitalization).
| Unadjusted | Adjusted | |||
|---|---|---|---|---|
| Environmental factor (Unit) | OR (95% CI) | p-value | OR (95% CI) | p-value |
| 1 week | ||||
| Temperature (°C) | 0.99 (0.99; 0.99) | <0.001 | 0.99 (0.98; 0.99) | <0.001 |
| Humidity (%) | 0.99 (0.99; 1.00) | 0.117 | 0.99 (0.98; 0.99) | 0.002 |
| NO2 (Bg/m3) | 1.02 (1.01; 1.03) | 0.020 | 1.01 (0.99; 1.03) | 0.229 |
| SO2 (Bg/m3) | 1.00 (0.99; 1.01) | 0.641 | 1.00 (0.99; 1.01) | 0.711 |
| O3 (Bg/m3) | 0.98 (0.98; 0.99) | <0.001 | 0.98 (0.97; 0.99) | <0.001 |
| PM10 (Bg/m3) | 0.99 (0.98; 1.01) | 0.511 | 0.98 (0.97; 0.99) | 0.034 |
| CO (Bg/m3) | 1.04 (1.03; 1.05) | <0.001 | 1.04 (1.02; 1.06) | <0.001 |
| 1.5 weeks | ||||
| Temperature (°C) | 0.99 (0.99; 1.01) | 0.167 | 0.99 (0.99; 0.99) | 0.024 |
| Humidity (%) | 1.00 (0.99; 1.01) | 0.475 | 0.99 (0.99; 1.01) | 0.236 |
| NO2 (Bg/m3) | 0.97 (0.96; 0.98) | <0.001 | 0.97 (0.96; 0.98) | <0.001 |
| SO2 (Bg/m3) | 0.99 (0.99; 1.01) | 0.503 | 1.00 (0.99; 1.01) | 0.908 |
| O3 (Bg/m3) | 0.99 (0.98; 0.99) | <0.001 | 0.98 (0.97; 0.99) | <0.001 |
| PM10 (Bg/m3) | 0.96 (0.95; 0.97) | <0.001 | 0.96 (0.94; 0.97) | <0.001 |
| CO (Bg/m3) | 1.03 (1.02; 1.04) | <0.001 | 1.04 (1.03; 1.06) | <0.001 |
| 2 weeks | ||||
| Temperature (°C) | 0.99 (0.99; 0.99) | <0.001 | 0.99 (0.99; 0.99) | <0.001 |
| Humidity (%) | 0.99 (0.99; 1.01) | 0.440 | 0.99 (0.99; 0.99) | 0.043 |
| NO2 (Bg/m3) | 1.03 (1.01; 1.04) | <0.001 | 1.02 (1.01; 1.04) | 0.002 |
| SO2 (Bg/m3) | 0.99 (0.99; 1.01) | 0.187 | 0.99 (0.99; 1.01) | 0.107 |
| O3 (Bg/m3) | 0.98 (0.97; 0.98) | <0.001 | 0.98 (0.97; 0.99) | <0.001 |
| PM10 (Bg/m3) | 0.99 (0.98; 1.01) | 0.222 | 0.97 (0.96; 0.99) | 0.001 |
| CO (Bg/m3) | 1.05 (1.03; 1.06) | <0.001 | 1.04 (1.03; 1.06) | <0.001 |
| 3 weeks | ||||
| Temperature (°C) | 1.01 (1.01; 1.01) | 0.029 | 1.00 (0.99; 1.00) | 0.206 |
| Humidity (%) | 1.00 (1.00; 1.00) | 0.858 | 1.00 (1.00; 1.00) | 0.650 |
| NO2 (Bg/m3) | 1.03 (1.02; 1.05) | <0.001 | 1.02 (1.01; 1.03) | 0.017 |
| SO2 (Bg/m3) | 0.99 (0.99; 1.00) | 0.715 | 0.99 (0.99; 1.01) | 0.551 |
| O3 (Bg/m3) | 0.97 (0.97; 0.98) | <0.001 | 0.97 (0.97; 0.98) | <0.001 |
| PM10 (Bg/m3) | 1.01 (0.99; 1.02) | 0.452 | 0.98 (0.97; 0.99) | 0.026 |
| CO (Bg/m3) | 1.05 (1.04; 1.06) | <0.001 | 1.05 (1.03; 1.06) | <0.001 |
NO2, nitrogen dioxide; SO2, sulfur dioxide; O3, ozone; PM10, particulate matter up to 10 μg/ m3 in size; CO: carbon monoxide; OR, odds ratio; 95% CI, 95% of confidence interval.