Table 1.
Characteristics of 46 day-shift workers and 84 rotating-shift workers randomly selected from the Nurses’ Health Study II cohort
| Day-shift workers | Rotating-shift workers | |
|---|---|---|
| Age, in years, mean (SD) | 53.7 (4.4) | 52.1 (4.9) |
| Body-mass index, in kg/m2, mean (SD) | 26.3 (6.3) | 27.9 (6.8) |
| History of rotating-shift work during 1989–2005, in years, N (%) | ||
| None | 24 (52) | 16 (19) |
| 1–4 | 6 (13) | 9 (11) |
| 5–9 | 4 (9) | 16 (19) |
| ≥10 | 9 (20) | 29 (34) |
| Missing | 3 (6) | 14 (17) |
| History of night-shift work in the past 30 days, in number of nights, N (%) | ||
| None | 37 (81) | 2 (2) |
| 1–4 | 6 (13) | 15 (18) |
| 5–9 | 2 (4) | 31 (37) |
| ≥10 | 0 (0) | 35 (42) |
| Missing | 1 (2) | 1 (1) |
| Alcohol intake, ≥2 drinks/week, N (%) | 16 (35) | 26 (31) |
| Smoking history, N (%) | ||
| Never | 43 (94) | 81 (97) |
| Ever | 2 (4) | 1 (1) |
| Missing | 1 (2) | 2 (2) |
| Exercise, in hours/week, N (%) | ||
| 0–1 | 16 (34) | 20 (24) |
| 1–3 | 12 (26) | 28 (33) |
| 3–6 | 9 (20) | 22 (26) |
| ≥6 | 9 (20) | 14 (17) |
| Currently pregnant or breast feeding, N (%) | 1 (2) | 3 (4) |
| HRT use, N (%) | 4 (9) | 4 (5) |
| Sleeping pill use, N (%) | 14 (30) | 39 (46) |
| NSAID use, N (%) | 13 (28) | 35 (42) |
| Beta-blocker use, N (%) | 4 (9) | 6 (7) |
| Benzodiazepene use, N (%) | 1 (2) | 1 (1) |
| Antidepressant use, N (%) | 4 (9) | 10 (12) |
HRT=hormone replacement therapy; NSAID=non-steroidal anti-inflammatory drug; SD=standard deviation