Table 1 Demographic, occupational, health, and work-related psychosocial characteristics of study participants and bivariate associations between these factors and years worked at night among women ( n  = 2,100)
|  | All ( n  = 2,100) | Years worked at night | p -value | ||
|---|---|---|---|---|---|
<1 ( n  = 447) | 1 to 9 ( n  = 1,008) | ≥10 ( n  = 645) | |||
Age, mean (SD) | 39.5 (9.8) | 38.2 (10.9) | 36.6 (9.1) | 44.9 (7.5) | <0.001 |
Per capita income (USD)a, mean (SD) | 1,061.1 (709.2) | 1,001.6 (680.5) | 1,053.9 (689.2) | 1,113.6 (755.3) | 0.033 |
Weekly hours worked, mean (SD) | 54.2 (19.1) | 47.8 (17.5 | 54.4 (18.8) | 57.8 (19.3) | <0.001 |
Years at work in nursing, mean (SD) | 15.2 (9.7) | 15.18 (9.8) | 15.2 (9.6) | 15.6 (9.6) | 0.697 |
BMI at 20Â years, mean (SD) | 21.1 (3.3) | 21.1 (3.2) | 21.2 (3.4) | 21.1 (3.4) | 0.604 |
BMI (current), mean (SD) | 26.1 (5.1) | 25.4 (4.8) | 25.7 (4.9) | 27.2 (5.4) | <0.001 |
Number of biological children, mean (SD) | 0.97 (1.0) | 0.80 (0.94) | 0.88 (0.99) | 1.23 (1.03) | <0.001 |
Marital status (% married) | 58.9 | 56.8 | 59.8 | 58.9 | 0.563 |
Smoking status | Â | Â | Â | Â | Â |
 Never smoker | 76.6 | 77.7 | 80.8 | 69.2 | <0.001 |
 Ex-smoker | 15.0 | 15.0 | 11.7 | 20.3 | |
 Current smoker | 8.4 | 7.4 | 7.5 | 10.5 | |
Alcohol consumption | Â | Â | Â | Â | Â |
 Abstained | 38.9 | 41.6 | 40.9 | 34.0 | 0.083 |
 Low | 20.0 | 19.2 | 18.8 | 22.6 | |
 Medium | 32.2 | 32.1 | 32.8 | 34.4 | |
 High | 7.9 | 6.9 | 7.5 | 9.0 | |
Physical activity (% yes) | 30.2 | 32.4 | 30.0 | 29.0 | 0.464 |
Sleep time, mean (SD) | 6.9 (1.5) | 6.9 (1.5) | 6.9 (1.5) | 7.0 (1.6) | 0.235 |