Effects of long working hours and the night shift on severe sleepiness among workers with 12-hour shift systems for 5 to 7 consecutive days in the automobile factories of Korea

Mia Son, Jeong Ok Kong, Sang Baek Koh, Jaeyoung Kim, Mikko Härmä

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

We investigated the effects of 12-hour shift work for five to seven consecutive days and overtime on the prevalence of severe sleepiness in the automobile industry in Korea. [Correction added after online publication 28 Nov: Opening sentence of the summary has been rephrased for better clarity.] A total of 288 randomly selected male workers from two automobile factories were selected and investigated using questionnaires and sleep-wake diaries in South Korea. The prevalence of severe sleepiness at work [i.e. Karolinska Sleepiness Scale (KSS) score of 7 or higher] was modeled using marginal logistic regression and included theoretical risk factors related to working hours and potential confounding factors related to socio-economic status, work demands, and health behaviors. Factors related to working hours increased the risk for severe sleepiness at the end of the shift in the following order: the night shift [odds ratio (OR): 4.7; 95% confidence interval (CI): 3.6-6.0)], daily overtime (OR: 2.2; 95% CI: 1.7-2.9), weekly overtime (OR: 1.6; 95% CI: 1.0-2.6), and night overtime (OR: 1.6; 95% CI: 0.8-3.0). Long working hours and shift work had a significant interactive effect for severe sleepiness at work. Night shift workers who worked for 12 h or more a day were exposed to a risk of severe sleepiness that was 7.5 times greater than day shift workers who worked less than 11 h. Night shifts and long working hours were the main risk factors for severe sleepiness among automobile factory workers in Korea. Night shifts and long working hours have a high degree of interactive effects resulting in severe sleepiness at work, which highlight the need for immediate measures to address these characteristics among South Korean labor force patterns.

Original languageEnglish
Pages (from-to)385-394
Number of pages10
JournalJournal of Sleep Research
Volume17
Issue number4
DOIs
Publication statusPublished - 2008 Dec 1

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Automobiles
Korea
Odds Ratio
Confidence Intervals
Republic of Korea
Health Behavior
Publications
Industry
Sleep
Logistic Models
Economics

All Science Journal Classification (ASJC) codes

  • Cognitive Neuroscience
  • Behavioral Neuroscience

Cite this

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title = "Effects of long working hours and the night shift on severe sleepiness among workers with 12-hour shift systems for 5 to 7 consecutive days in the automobile factories of Korea",
abstract = "We investigated the effects of 12-hour shift work for five to seven consecutive days and overtime on the prevalence of severe sleepiness in the automobile industry in Korea. [Correction added after online publication 28 Nov: Opening sentence of the summary has been rephrased for better clarity.] A total of 288 randomly selected male workers from two automobile factories were selected and investigated using questionnaires and sleep-wake diaries in South Korea. The prevalence of severe sleepiness at work [i.e. Karolinska Sleepiness Scale (KSS) score of 7 or higher] was modeled using marginal logistic regression and included theoretical risk factors related to working hours and potential confounding factors related to socio-economic status, work demands, and health behaviors. Factors related to working hours increased the risk for severe sleepiness at the end of the shift in the following order: the night shift [odds ratio (OR): 4.7; 95{\%} confidence interval (CI): 3.6-6.0)], daily overtime (OR: 2.2; 95{\%} CI: 1.7-2.9), weekly overtime (OR: 1.6; 95{\%} CI: 1.0-2.6), and night overtime (OR: 1.6; 95{\%} CI: 0.8-3.0). Long working hours and shift work had a significant interactive effect for severe sleepiness at work. Night shift workers who worked for 12 h or more a day were exposed to a risk of severe sleepiness that was 7.5 times greater than day shift workers who worked less than 11 h. Night shifts and long working hours were the main risk factors for severe sleepiness among automobile factory workers in Korea. Night shifts and long working hours have a high degree of interactive effects resulting in severe sleepiness at work, which highlight the need for immediate measures to address these characteristics among South Korean labor force patterns.",
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Effects of long working hours and the night shift on severe sleepiness among workers with 12-hour shift systems for 5 to 7 consecutive days in the automobile factories of Korea. / Son, Mia; Kong, Jeong Ok; Koh, Sang Baek; Kim, Jaeyoung; Härmä, Mikko.

In: Journal of Sleep Research, Vol. 17, No. 4, 01.12.2008, p. 385-394.

Research output: Contribution to journalArticle

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