Table 1 Distribution of pre-COVID demographics by COVID-19 infection
All | COVID-19 cases | Non-cases | P-value | |
|---|---|---|---|---|
N = 42,621 | N = 6,560 | N = 36,061 | ||
n (%) | n (%) | n (%) | ||
Age, years | ||||
≤ 30 | 2,760 (6.48) | 589 (8.98) | 2,171 (6.02) | < 0.001 |
31–44 | 8,855 (20.78) | 1,795 (27.36) | 7,060 (19.58) | |
45–60 | 12,167 (28.55) | 2,491 (37.97) | 9,676 (26.83) | |
> 60 | 18,839 (44.20) | 1,685 (25.69) | 17,154 (47.57) | |
Gender | ||||
Female | 23,227 (54.50) | 3,735 (56.94) | 19,492 (54.05) | < 0.001 |
Male | 19,394 (45.50) | 2,825 (43.06) | 16,569 (45.95) | |
Smoking | ||||
Non-smoker | 26,131 (61.31) | 4,268 (65.06) | 21,863 (60.63) | < 0.001 |
Ex-smoker | 10,171 (23.86) | 1,425 (21.72) | 8,746 (24.25) | |
Smoker (or stopped < 1year ago) | 6,319 (14.83) | 867 (13.22) | 5,452 (15.12) | |
Body mass index (BMI), kg/m2 | ||||
< 25 | 21,099 (49.50) | 3,219 (49.07) | 17,880 (49.58) | 0.734 |
25–29.99… | 15,682 (36.79) | 2,430 (37.04) | 13,252 (36.75) | |
≥ 30 | 5,840 (13.70) | 911 (13.89) | 4,929 (13.67) | |
Raised on a farm | ||||
No | 37,976 (89.10) | 5,932 (90.43) | 32,044 (88.86) | < 0.001 |
Yes | 4,645 (10.90) | 628 (9.57) | 4,017 (11.14) | |
Rural residence during childhood | ||||
No | 29,808 (69.94) | 4,711 (71.81) | 25,097 (69.6) | < 0.001 |
Yes | 12,813 (30.06) | 1,849 (28.19) | 10,964 (30.4) | |
Highest education attained | ||||
Less than high school | 6,824 (16.01) | 730 (11.13) | 6,094 (16.9) | < 0.001 |
High school | 19,355 (45.41) | 3,144 (47.93) | 16,211 (44.95) | |
Tertiary education | 16,442 (38.58) | 2,686 (40.95) | 13,756 (38.15) | |
Social class classification† | ||||
1 (managers) | 2,276 (5.34) | 368 (5.61) | 1,908 (5.29) | < 0.001 |
2 (professionals) | 8,011 (18.80) | 1,354 (20.64) | 6,657 (18.46) | |
3 (technicians and associate professionals) | 5,645 (13.24) | 906 (13.81) | 4,739 (13.14) | |
4 (office support workers) | 3,440 (8.07) | 478 (7.29) | 3,012 (8.35) | |
5 (service and sale workers) | 9,508 (22.31) | 1,557 (23.73) | 7,875 (21.84) | |
6 (skilled agriculture/forestry/fishery workers) | 1,440 (3.38) | 211 (3.22) | 1,255 (3.48) | |
7 (craft and related trade workers) | 2,540 (5.96) | 366 (5.58) | 2,174 (6.03) | |
8 (plant and machine operators/assemblers) | 1,907 (4.47) | 277 (4.22) | 1,630 (4.52) | |
9 (elementary occupations) | 7,854 (18.43) | 1,043 (15.9) | 6,811 (18.89) | |
0 (military personnel) | 0 yy | 0 (0) | 0 (0) | |
Clinician-diagnosed COPD | ||||
No | 41,374 (97.07) | 6,401 (97.58) | 34,973 (96.98) | 0.009 |
Yes | 1,247 (2.93) | 159 (2.42) | 1,088 (3.02) | |
Clinician-diagnosed asthma | ||||
No | 38,965 (91.42) | 5,884 (89.7) | 33,081 (91.74) | < 0.001 |
Yes | 3,656 (8.58) | 676 (10.3) | 2,980 (8.26) | |
Allergic asthma (asthma + rhinitis) | ||||
No | 39,489 (92.65) | 5,941 (90.56) | 33,548 (93.03) | < 0.001 |
Yes | 3,132 (7.35) | 619 (9.44) | 2,513 (6.97) | |
Any respiratory symptom‡ | ||||
No | 30,357 (71.23) | 4,520 (68.9) | 25,837 (71.65) | < 0.001 |
Yes | 12,264 (28.77) | 2,040 (31.1) | 10,224 (28.35) | |
Number of comorbidities§ | ||||
0 | 16,952 (39.77) | 2,602 (39.66) | 14,350 (39.79) | 0.911 |
1 | 12,433 (29.17) | 1,906 (29.05) | 10,527 (29.19) | |
≥ 2 | 13,236 (31.06) | 2,052 (31.28) | 11,184 (31.01) | |
Number of "severe" comorbidities (COPD, diabetes) | ||||
0 | ||||
1 | 39,262 (92.12) | 6,121 (93.31) | 33,141 (91.9) | 0.001 |
2 | 3,164 (7.42) | 413 (6.3) | 2,751 (7.63) | |
195 (0.46) | 26 (0.4) | 169 (0.47) | ||
Number of "moderately severe" comorbidities (asthma, hypertension) | ||||
0 | ||||
1 | 31,093 (72.95) | 4,997 (76.17) | 26,096 (72.37) | < 0.001 |
2 | 10,450 (24.52) | 1,426 (21.74) | 9,024 (25.02) | |
1,078 (2.53) | 137 (2.09) | 941 (2.61) | ||
Number of "mild" comorbidities (eczema, rhinitis, sleep disorder) | ||||
0 | ||||
1 | 21,790 (51.13) | 3,161 (48.19) | 18,629 (51.66) | < 0.001 |
≥ 2 | 13,818 (32.42) | 2,166 (33.02) | 11,652 (32.31) | |
7,013 (16.45) | 1,233 (18.80) | 5,780 (16.03) |