Table 1.
Characteristics of study participants by survival status in China
| Variable | Deceased (n = 3,934) | Alive (n = 67,874) | p valueb |
|---|---|---|---|
| Environmental factors | |||
| Exposure window Ia | |||
| Temperature (°C) | 5.26 ± 2.82 | 5.73 ± 4.11 | 0.0029 |
| Relative humidity (%) | 81.43 ± 9.41 | 79.18 ± 11.36 | <0.0001 |
| PM2.5 (μg/m3) | 54.01 ± 14.92 | 51.87 ± 20.25 | <0.0001 |
| PM10 (μg/m3) | 62.32 ± 16.33 | 60.81 ± 22.38 | <0.0001 |
| O3 (μg/m3) | 54.71 ± 7.73 | 55.84 ± 8.45 | <0.0001 |
| SO2 (μg/m3) | 7.43 ± 2.01 | 7.75 ± 3.49 | <0.0001 |
| NO2 (μg/m3) | 22.78 ± 5.81 | 20.34 ± 6.38 | <0.0001 |
| Exposure window IIa | |||
| Temperature (°C) | 7.27 ± 3.04 | 16.27 ± 2.06 | <0.0001 |
| Relative humidity (%) | 79.47 ± 6.30 | 66.44 ± 10.45 | <0.0001 |
| PM2.5 (μg/m3) | 44.71 ± 15.62 | 29.62 ± 7.23 | <0.0001 |
| PM10 (μg/m3) | 53.95 ± 16.76 | 55.57 ± 11.31 | <0.0001 |
| O3 (μg/m3) | 55. 13 ± 9.31 | 80.33 ± 9.82 | <0.0001 |
| SO2 (μg/m3) | 7.41 ± 1.80 | 9.46 ± 2.63 | <0.0001 |
| NO2 (μg/m3) | 20 .94 ± 6.17 | 28.98 ± 7.02 | <0.0001 |
| Age group (n, %) | <0.0001 | ||
| <25 years | 6 (0.15) | 3,493 (5.15) | |
| 25–64 years | 1,146 (29.13) | 50,111 (73.83) | |
| ≥65 years | 2,782 (70.72) | 14,270 (21.02) | |
| Sex (n, %) | <0.0001 | ||
| Male | 2,515 (63.93) | 33,659 (49.59) | |
| Female | 1,419 (36.07) | 34,215 (50.41) | |
| Days between symptom onset and diagnosis (n, %) | <0.0001 | ||
| <7 days | 1,362 (4.34) | 29,995 (95.66) | |
| 7–14 days | 1,557 (5.89) | 24,859 (94.11) | |
| ≥14 days | 1,015 (7.23) | 13,020 (92.77) | |
| Occupation (n, %) | <0.0001 | ||
| Medical-related | 21 (0.53) | 2,614 (3.85) | |
| Service-related | 15 (0.38) | 1,709 (2.52) | |
| Office worker | 226 (5.74) | 15,435 (22.74) | |
| Homemaker | 3,226 (82.00) | 38,632 (56.92) | |
| Others | 446 (11.34) | 9,484 (13.97) | |
| Residence (n, %) | <0.0001 | ||
| Permanent | 2,476 (62.94) | 48,055 (70.80) | |
| Temporary | 1,458 (37.06) | 19,819 (29.20) | |
| Severity (n, %) | <0.0001 | ||
| Mild | 806 (20.49) | 28,088 (41.38) | |
| Moderate | 597 (15.18) | 28,199 (41.55) | |
| Severe | 1,285 (32.66) | 10,081 (14.85) | |
| Critical | 1,246 (31.67) | 1,506 (2.22) | |
| Hospital transfer (n, %) | 0.1754 | ||
| No | 2,927 (74.40) | 49,825 (73.41) | |
| Yes | 1,007 (25.60) | 18,049 (26.59) | |
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.
a
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.
b
p values were calculated by t test, χ2 test or Fisher's exact test, as appropriate.