Table 1.
Characteristics of the participants (N = 385).
| n (%) | |
|---|---|
| Profession | |
| Healthcare workers | 279 (72) |
| Other | 106 (28) |
| Ethnicity | |
| Japanese | 376 (98) |
| Non-Japanese Asians | 9 (2) |
| Sex | |
| Male | 126 (33) |
| Female | 259 (67) |
| Age (years) | |
| Median (interquartile range) | 43 (34–50) |
| 20–29 | 63 (16) |
| 30–39 | 88 (23) |
| 40–49 | 132 (34) |
| 50–59 | 88 (23) |
| 60–64 | 14 (4) |
| Body mass index（kg/m2） | |
| Median (interquartile range) | 21.7 (19.9–23.7) |
| <18.5 | 40 (10) |
| 18.5–25 | 279 (72) |
| ≥25 | 66 (17) |
| Oral administration of steroids or immunosuppressants (previous 6 months) | |
| Yes | 9 (2) |
| Cigarette smoking habits | |
| Non-smoker | 313 (81) |
| Ex-smoker | 57 (15) |
| Current smoker | 15 (4) |
| Alcohol drinking habits | |
| Non-drinker | 113 (29) |
| Ex-drinker | 33 (9) |
| Current drinker | 239 (62) |