Sleep Problems & Worker Injuries: Research Findings


The dangers of a sleep deprived workforce have been clearly demonstrated throughout research; however, the association between sleep quality and work injury risk has been an open question of interest among researchers.

Conflicting results have come from studies examining the variables that potentially modulate the association between sleep quality and workplace injuries. A recent meta-analysis of 27 observational studies found that sleep problems increase the risk of workplace injuries by 62 percent (Uehli et al., 2014).

Because of this, Swiss researchers looked to better understand the relationship between sleep problems and workplace injuries. Their findings, which were recently published in the Journal of Sleep Research, provide valuable insights into the relationship between sleep problems and the risk of work injuries.

We summarize and highlight the valuable, key points this research publication.

Goal of Study

According to the authors, "the aim of the study was to provide further evidence for the relationship between sleep quality and work injury and to identify factors that may modify this association.

Factors considered for the effect modification were gender, age, job risk, shift or night work, sleep duration, weekly working hours and co-morbid conditions."

Study Population

The case-control study included 180 cases and 551 controls, all of whom were recruited through the emergency department of the University Hospital in Basil, Switzerland.

To be included in the study, participants were required to meet the following criteria:

1. Age between 18 to 65 years

2. Hospital admission from a work injury that had occurred within the previous 48 hours

3. Moderate or severe work injury

4. Proficient in German

5. Adequate general mental condition to complete the questionnaire


The well-validated and scientifically accepted Pittsburgh Sleep Quality Index (PSQI) was used to retrospectively measure sleep quality in the four weeks prior to the work injury. Poor sleep quality was defined as a PSQI score greater than 5.

Work injuries were defined according to Swiss law, and excludes repetitive strain injuries and commuting accidents.

Variables that were measured included:

  • Sleep quality based on PSQI Score (>5 = poor sleep quality)
  • Objectively diagnosed sleep disorders (self-reported)
  • Reported sleep duration
  • Type of work injury (8 categories)
  • Sociodemographic factors (gender, age, highest education and occupational status)
  • Work-related questions (primary job, shift or night work, weekly working hours and perceived work stress)

Research Findings

There was a dose-response relationship between sleep problem severity and the odds of a workplace injury occurring.

Workers were 2x more likely to suffer a work injury if diagnosed with a sleep disorder.

Workers with a diagnosed sleep disorder AND suffering from poor sleep quality had a 3x greater risk of a work injury.

For each 1 unit increase in PSQI score, work injury risk increased by 20-30% among participants who were:

  • Males 
  • Older workers (>30 years) 
  • Participants with high risk jobs
  • Working 50 hours per week or more 
  • Daytime workers
  • Short sleepers (

Also, for each 1 unit increase in PSQI score, the likelihood of previous work injuries increased by 12%.

Research Implications 

These findings are relevant and valuable because:

  • An increasing number of older individuals in the workforce (Auer and Fortuny, 2000)
  • An increasing number of people working long hours (Jacobs and Gerson, 2004) 
  • A decreasing average sleep duration among the general population (Kronholm et al., 2008)

Want to learn more about fatigue and workplace safety? 

Interested in how worker fatigue is impacting your workers? Check out a few of our articles and white papers that highlight important fatigue & safety finding. 

Relevant articles from CIRCADIAN's Shifting Work Perspectives:

CIRCADIAN White Papers

Biocompatible Shift Scheduling                 The Myths & Realities of Fatigue
Biocompatible Shift Scheduling Myths & Realities of Fatigue White Paper

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Additional Info

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