Table 1.
Demographic characteristics of subjects
| Variables | GERD-positive N = 392; N (%) | GERD-negative N = 825; N (%) | χ2 | P | |
|---|---|---|---|---|---|
| Sex | M | 365 (93.1) | 775 (93.9) | 0.307 | 0.580 |
| F | 27 (6.9) | 50 (6.1) | |||
| Age(years) | <30 | 15 (3.8) | 48 (5.8) | 11.748 | 0.008 |
| 30–39 | 114 (29.1) | 301 (36.4) | |||
| 40–49 | 184 (46.9) | 353 (42.7) | |||
| ≥50 | 79 (20.2) | 123 (15.1) | |||
| Education (years) | Low (<10) | 6 (1.5) | 13 (1.5) | 0.308 | 0.959 |
| Middle (10–13) | 101 (25.7) | 219 (26.5) | |||
| High (>13) | 285(72.8) | 593 (72.0) | |||
| Marital status | With spouse | 329 (83.9) | 674 (81.6) | 4.485 | 0.214 |
| Single | 57 (14.5) | 142 (17.2) | |||
| Divorced | 6 (1.6) | 6 (0.8) | |||
| Others | 0 (0.0) | 3 (0.4) | |||
| Working period (years) | <3 | 53 (13.5) | 151 (18.3) | 10.647 | 0.014 |
| 4–7 | 32 (8.1) | 101 (12.2) | |||
| 8–11 | 76 (19.3) | 147 (17.8) | |||
| ≥12 | 231 (59.1) | 426 (51.7) | |||
| Task | EMS | 97 (24.7) | 200 (24.2) | 0.328 | 0.955 |
| Rescue | 40 (10.2) | 80 (9.7) | |||
| Firefighting | 216 (55.1) | 455 (55.2) | |||
| Administration | 39 (10.0) | 90 (10.9) | |||
| Working pattern | Shift work | 342 (87.2) | 697 (84.5) | 1.621 | 0.203 |
| Daytime work | 50 (12.8) | 128 (15.5) |
Note: M: male, F: female, N: number, GERD: gastroesophageal reflux disease, EMS: emergency medical service.