To clarify the relationship between perceived job stress and sleep habits in Japanese healthy daytime workers, a total of 334 female employees of an electric equipment manufacturing company (age, 23 to 59, mean, 30.3 years) were surveyed using mailed questionnaires. Perceived job stress, i.e., job control, quantitative workload, variance in workload, skill underutilization, cognitive demands, and buffer factors as social support from supervisor, coworker, and family or friends was assessed by means of the Japanese version of the NIOSH job stress questionnaire; mean overtime per month was also calculated. The workers were asked about eleven sleep habits with greater score indicating poor sleep quality (daily sleeping hours (DSH), insufficiency of sleep, time to fall asleep (TFA), awakening during sleep (ADS), early morning awakening (EMA), sleeping poorly at night, dozing or napping in daytime, excessive daytime sleepiness (EDS) at work, being absent from or late for work due to oversleeping, use of medication to help sleep, and sought medical help for sleep problems).
After controlling for age by partial correlation coefficients in all workers, skill underutilization was positively correlated with DSH; cognitive demands were inversely correlated with dozing or napping in daytime and EDS at work; overtime was inversely correlated with DSH, and positively correlated with sleeping poorly at night. Also, supervisor support was inversely correlated with sufficiency of sleep and EMA; coworker support was inversely correlated with ADS; and support from family or friends were inversely correlated with insufficiency of sleep, TFA, ADS, and EMA. In addition, unmarried women showed an inverse correlation between quantitative workload and EDS at work; cognitive demands were positively correlated with sought medical help for sleep problems; overtime was inversely correlated with DSH. Married women showed a positive relation between quantitative workload and insufficiency of sleep or being absent from or late for work due to oversleeping; supervisor support was related to use of medication to help sleep and support from family or friends were inversely correlated with ADS and EMA.
The results suggest that job stress is associated with sleep habits in female daytime workers in Japan. Although some differences were found in married and unmarried women, sleep quality might be affected by job demands and social support at workplace and by family or friends.
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