Table 2.
Hazard ratios and 95% CIs for case fatalities due to COVID-19 associated with environmental factors of two exposure windows in China
| Variable | Hazard ratio (95% CI) |
p valueb | |||
|---|---|---|---|---|---|
| Exposure window Ia |
Exposure window IIa |
||||
| Crudec | Adjustedd | Crudec | Adjustedd | ||
| Temperature | 1.02 (1.01, 1.03) | 1.03 (1.01, 1.04) | 1.27 (1.26, 1.28) | 3.20 (3.15, 3.25) | <0.01 |
| PM2.5 | 1.05 (1.04, 1.07) | 1.11 (1.09, 1.13) | 1.56 (1,54, 1.58) | 1.39 (1.36, 1.42) | <0.01 |
| PM10 | 1.04 (1.02, 1.05) | 1.10 (1.08, 1.13) | 1.43 (1.42, 1.44) | 1.18 (1.16, 1.21) | <0.01 |
| NO2 | 1.69 (1.93, 1.75) | 1.27 (1.19, 1.35) | 1.22 (1.14, 1.30) | 1.37 (1.29, 1.45) | 0.08 |
| SO2 | 0.70 (0.62, 0.79) | 1.10 (0.95, 1.27) | 1.13 (0.91, 1.40) | 1.51 (1.22, 1.88) | 0.20 |
| O3 | 0.84 (0.81, 0.87) | 1.09 (1.03, 1.14) | 1.27 (1.21, 1.33) | 1.25 (1.20, 1.30) | <0.01 |
Note: PM2.5, particulate matter with an aerodynamic diameter ≤2.5 μm; PM10, particulate matter with an aerodynamic diameter ≤10 μm; SO2, sulfur dioxide; NO2, nitrogen dioxide; O3, ozone.
Exposure window I represents the mean exposure value from the date of symptom onset to the date of diagnosis; exposure window II represents the mean exposure value from the date of diagnosis to the date of death or the end of the study.
Estimated using likelihood ratio test by comparing adjusted HRs for different windows.
Crude model, without any adjustment.
Multivariate model, adjusted for age, sex, occupation, residence, severity of illness, location, transfer history, temporal trend, lockdown, city-level GDP, hospital beds per 1,000 persons, temperature (only for the pollutants), and relative humidity.