Table 3.
Shift Work Characteristics of Participants in the Korea Nurses' Health Study
| Variables | Total (n = 20,613) |
|---|---|
| Current work status | |
| Full-time | 18,827 (91.3) |
| Part-time | 1784 (8.7) |
| Missing | 2 (0.0) |
| Night shifts, while working as a nurse | |
| Never | 2042 (9.9) |
| Ever | 18,231 (88.4) |
| Missing | 340 (1.6) |
| Total number of years on night shiftsa | |
| Mean (SD) | 5.3 (4.3) |
| <1 | 2112 (11.6) |
| 1–4 | 7420 (40.7) |
| 5–9 | 5510 (30.2) |
| 10–14 | 2380 (13.1) |
| 15–19 | 675 (3.7) |
| ≥20 | 134 (0.7) |
| Night shifts, during the past year | |
| Never | 6593 (32.0) |
| Ever | 13,990 (67.9) |
| Missing | 30 (0.1) |
| Mean number of night shift worked per monthb | |
| Mean (SD) | 6.6 (2.3) |
| 1–4 | 1790 (12.8) |
| 5–7 | 8404 (60.1) |
| ≥8 | 3796 (27.1) |
Data are expressed as the mean (SD) or as number (%).
a
Among the 18,231 participants who had worked night shifts while working as nurses.
b
Among the 13,990 participants who had worked night shifts during the past year.