Table 1. Characteristics of the participants in three cross-sectional surveys in 2013–2015 and the respective cohorts in 2013–2014 and 2014–2015.
| Characteristic | Cross-sectional surveys |
P value* | Cohorts (Year) |
P value* | |||
|---|---|---|---|---|---|---|---|
| November 2013 | April 2014 | April 2015 | 2013–2014 (Nov 2013–Apr 2014) | 2014–2015 (Apr 2014–Apr 2015) | |||
| Participant category | <0.001 | <0.001 | |||||
| Poultry workers | 1258 (33.2) | 1056 (30.2) | 1123 (34.5) | 791 (30.9) | 512 (25.4) | ||
| Swine workers | 1332 (35.1) | 1254 (35.8) | 998 (30.7) | 862 (33.6) | 568 (28.2) | ||
| General population | 1200 (31.7) | 1188(34.0) | 1135 (34.9) | 910 (35.5) | 932 (46.3) | ||
| Sex | 0.051 | 0.529 | |||||
| Male | 1933 (51.0) | 1686 (48.3) | 1595 (49.0) | 1224 (47.8) | 941 (46.8) | ||
| Female | 1855 (49.0) | 1807 (51.7) | 1658 (51.0) | 1338 (52.2) | 1068 (53.2) | ||
| Age group | 0.907 | 0.152 | |||||
| <50 years | 2200 (58.1) | 2018 (57.8) | 1871 (57.6) | 1435 (56.1) | 1085 (54.0) | ||
| ≥50 years | 1585 (41.9) | 1471 (42. 2) | 1377 (42.4) | 1124 (43.9) | 926 (46.0) | ||
| Having underlying disease | <0.001 | 0.121 | |||||
| No | 3489 (92.1) | 3278 (93.7) | 2950 (90.6) | 2349 (91.7) | 1868 (92.9) | ||
| Yes | 301 (7.9) | 219 (6.3) | 305 (9.4) | 214 (8.3) | 143 (7.1) | ||
| Total | 3790 (100) | 3498 (100) | 3256 (100) | — | 2563 (100) | 2012 (100) | — |
Note. Data are expressed as proportion (%) of participants, unless otherwise indicated.
*Compared using Pearson’s χ2 test.