| Author, Date |
Sample |
Description of Work Schedule |
Health or Safety Measure |
Statistical Methods Controls |
Results Reported by Authors |
| Duchon et al. 1997 |
30 underground male miners:
- Age not reported
- Canada |
- 8-h 3-shift rotation with M 41 h/wk changes to experimental 12-h day/night rotation (4 on, 4 off) with M 48 h/wk
- Control group: 8-h day shift, 40 h/wk |
- Tested pre-, mid-, post-shift for a week:
- 8-h rotation
- After 12-h rotation for 10 months
- Submaximal exercise testing
- Continuous heart rate monitoring
- Computerized test battery tested pursuit tracking, grammatical reasoning, choice reaction time, finger tapping |
- Three-way mixed design ANOVA
- Kruskal-Wallis one-way ANOVA |
- No significant main effects between 8- and 12-h shifts on neurobehavioral performance measures.
- Continuous heart rate findings showed pacing of work effort on 12-h shifts relative to 8-h shifts. The 12-h workers appeared to pace their work at a slower rate than the 8-h workers. |
| Fischer et al. 2000 |
22 male workers at a petrochemical plant:
- Age M 32.6;
- Brazil |
- 12-h day/night rapid rotation (2 - 3D, 2 - 3 N, 4 - 5 off)
- 48 M h/wk |
For 30 days, recorded subjective alertness at 2nd, 6th, 10th hour of day and night shifts using visual analog scale (10cm) from not at all alert to very alert. |
- Repeated measures ANOVA
- Tukey tests for post hoe comparisons |
Significant reduction in alertness (p < 0.001):
- Days, from 2nd hour to 10th hour.
- Nights, 10th hour reduced from 2nd and 6th hour.
- No reduction seen across successive night shifts. |
| Lipscomb et al. 2002a |
1,163 working nurses randomly selected from two states:
- Age M 45
- Women 95%
- United States |
One-time questionnaire:
- Work h/day: <= 8; 9 - 11; >=12
- Work h/wk: <= 40; 41 - 49; >=50
- Work days/wk: 1 - 5; 6- 7
- Day shift versus other
- Interactions: h/shift by h/wk |
One-time Nordic Survey of Musculoskeletal Symptoms |
Logistic regression adjusted for age |
- Compared to 8-h shift, >= 12-h/day increased risk for back disorders (OR 1.61, CI 1.05 - 2.48).
- Interactions suggested that >= 12-h /day combined with >= 40-h/week elevated risk for disorders of neck (OR 2.30, CI 1.03 - 5.11), shoulder (OR 2.48, CI 1.07 - 5.77), and back (OR 2.67, CI 1.26 - 5.66).
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