Table 1.
Baseline characteristics of the questionnaire participants.
| Baseline category | SARS-CoV-2–negative | SARS-CoV-2–positive | Suspected positive | p-value |
|---|---|---|---|---|
| Region | ||||
| East China | 781 (23.1%) | 1953 (29.03%) | 318 (17.79%) | p < 0.001 |
| South China | 267 (7.9%) | 461 (6.85%) | 120 (6.71%) | |
| Central China | 1279 (37.83%) | 1864 (27.71%) | 852 (47.65%) | |
| North China | 608 (17.98%) | 1565 (23.26%) | 252 (14.09%) | |
| Northeast China | 61 (1.8%) | 169 (2.51%) | 36 (2.01%) | |
| Northwest China | 120 (3.55%) | 283 (4.21%) | 77 (4.31%) | |
| Southwest China | 265 (7.84%) | 433 (6.44%) | 133 (7.44%) | |
| Sex | ||||
| Male | 1486 (43.95%) | 2736 (40.67%) | 601 (33.61%) | p < 0.001 |
| Female | 1895 (56.05%) | 3992 (59.33%) | 1187 (66.39%) | |
| Age | ||||
| Under 18 years | 53 (1.57%) | 58 (0.86%) | 23 (1.29%) | p < 0.001 |
| 18–29 years | 1878 (55.55%) | 2899 (43.09%) | 1161 (64.93%) | |
| 30–39 years | 398 (11.77%) | 1162 (17.27%) | 145 (8.11%) | |
| 40–49 years | 338 (10%) | 1099 (16.33%) | 161 (9%) | |
| 50–59 years | 343 (10.14%) | 839 (12.47%) | 153 (8.56%) | |
| 60–69 years | 259 (7.66%) | 491 (7.3%) | 94 (5.26%) | |
| 70–80 years | 82 (2.43%) | 142 (2.11%) | 44 (2.46%) | |
| Over 80 years | 30 (0.89%) | 38 (0.56%) | 7 (0.39%) | |
| Smoking | ||||
| Non-smoker | 3037 (89.83%) | 6147 (91.36%) | 1677 (93.79%) | p < 0.001 |
| 1–5 cigarettes every month | 41 (1.21%) | 120 (1.78%) | 17 (0.95%) | |
| 1–5 cigarettes per day | 63 (1.86%) | 134 (1.99%) | 23 (1.29%) | |
| 6–10 cigarettes per day | 64 (1.89%) | 130 (1.93%) | 29 (1.62%) | |
| 11–20 cigarettes per day | 112 (3.31%) | 134 (1.99%) | 22 (1.23%) | |
| More than cigarettes 20 per day | 64 (1.89%) | 63 (0.94%) | 20 (1.12%) | |
| Drinking | ||||
| Non-drinker | 1798 (53.18%) | 3223 (47.9%) | 1007 (56.32%) | p < 0.001 |
| 1–3 times a year | 1021 (30.2%) | 2175 (32.33%) | 560 (31.32%) | |
| 1–3 times a month | 363 (10.74%) | 925 (13.75%) | 156 (8.72%) | |
| 1–3 times a week | 144 (4.26%) | 338 (5.02%) | 38 (2.13%) | |
| Once a day or more | 55 (1.63%) | 67 (1%) | 27 (1.51%) | |
| Medical condition | ||||
| Chronic obstructive pulmonary disease | 18 (0.53%) | 46 (0.68%) | 14 (0.78%) | 0.518 |
| Emphysema | 7 (0.21%) | 33 (0.49%) | 10 (0.56%) | 0.071 |
| Respiratory diseases (asthma, chronic bronchitis, etc.) | 93 (2.75%) | 304 (4.52%) | 72 (4.03%) | p < 0.001 |
| Diabetes | 87 (2.57%) | 207 (3.08%) | 47 (2.63%) | 0.29 |
| Hypertension | 235 (6.95%) | 576 (8.56%) | 103 (5.76%) | p < 0.001 |
| Cardio-cerebrovascular disease | 67 (1.98%) | 164 (2.44%) | 34 (1.9%) | 0.205 |
| Chronic nephrosis | 12 (0.35%) | 37 (0.55%) | 8 (0.45%) | 0.399 |
| Chronic liver disease | 23 (0.68%) | 47 (0.7%) | 11 (0.62%) | 0.93 |
| Pregnancy | 13 (0.38%) | 70 (1.04%) | 1 (0.06%) | p < 0.001 |
| Malignant tumor in treatment | 8 (0.24%) | 18 (0.27%) | 2 (0.11%) | 0.483 |
| Malignant tumor after treatment | 22 (0.65%) | 69 (1.03%) | 12 (0.67%) | 0.1 |
| Benign tumor | 17 (0.5%) | 57 (0.85%) | 15 (0.84%) | 0.147 |
| Autoimmune disease | 46 (1.36%) | 113 (1.68%) | 19 (1.06%) | 0.12 |