Effects on employees of controlling working hours and working schedules.
BACKGROUND
High levels of control over working time and low variability in working hours have been associated with improved health-related outcomes. The potential mechanisms for this association remain unclear.


OBJECTIVE
To examine how work-time control and variability of working times are associated with fatigue recovery, sleep quality, work-life balance, and 'near misses' at work.


METHODS
Manufacturing sector employees completed a questionnaire that assessed work-time control, work-time variability, fatigue recovery, sleep quality, work-life balance and the frequency of near misses in the past 6 months. Mixed model analysis of covariance and multiple logistic regression analysis tested the main effects of work-time control and variability and their interaction, while adjusting for age, sex, work schedules, and overtime work in the past month. Subscales of work-time control were also investigated (control over daily working hours and over days off).


RESULTS
One thousand three hundred and seventy-two completed questionnaires were returned, a response rate of 69%. A significantly higher quality of sleep and better work-life balance were found in the 'high control with low variability' reference group than in the other groups. Significantly better recovery of fatigue was also observed in the group having control over days off with low variability. While near misses were more frequent in the group with high control over daily working hours coupled with high variability compared with the reference group this was not significant.


CONCLUSIONS
High work-time control and low variability were associated with favourable outcomes of health and work-life balance. This combined effect was not observed for the safety outcome addressed here.
National Institute of Occupational Safety and Health, Kawasaki, Japan. kubo@h.jniosh.go.jp
T
T
Kubo
M
M
Takahashi
F
F
Togo
X
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Liu
A
A
Shimazu
K
K
Tanaka
M
M
Takaya
D000328:Adult; D005221:Fatigue; D005260:Female; D006801:Humans; D007221:Industry; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016272:Occupational Health; D011788:Quality of Life; D012449:Safety; D012890:Sleep; D013997:Time Factors; D014940:Work Schedule Tolerance / Q000502:physiology* / Q000523:psychology*