Biomarkers of Sleep-Wake Disturbances in Night Shift Workers

Details

• Personal Author:
  Gumenyuk V
• Description:
  Shift Work Disorder (SWD) is a circadian rhythm disorder diagnosed when shift workers develop excessive sleepiness and/or insomnia that are temporally related to a work schedule that occurs during the physiologic sleep period (e.g., 11 PM to 7 AM five times per week, or 6:30 PM to 6:30 AM three times per week). Findings from laboratory simulations of shift work prior to this study suggested that SWD might be traced to a misalignment between an individual's circadian rhythm and their work-imposed sleep-wake schedule, such that they are forced to be awake during a period of natural sleepiness and attempt to sleep during a period of natural wakefulness. Using salivary melatonin samples collected at frequent and regular intervals, this study demonstrated that asymptomatic (healthy) shift workers have a mean melatonin onset near 5:00 AM, which is highly adaptive to night work. On the other hand, workers meeting criteria for SWD show a mean melatonin onset between 8:00 PM and 11:00 PM, which would be typical and well-adjusted for a day shift worker but is maladaptive for a night shift worker. Accordingly, this project was the first to conclusively link melatonin onset with SWD symptomatology in real night workers. Other important findings from this project relate to impaired neurophysiologic functioning during night shift hours. Using evoked response potentials, an electroencephalographic technique, reorienting of attention was found to be significantly attenuated in night workers with SWD compared to healthy night-working controls. Many SWD patients also show pathological, even dangerous, levels of sleep propensity during shift hours on the Multiple Sleep Latency Test (MSLT), although recent post-hoc analyses stratifying the sample by symptomatology have clarified that high MSLT scores are variable in their presentation, depending on the symptom profile of the affected worker. Finally, during shift work hours, acute sleep deprivation (like that commonly experienced by shift workers) was shown to decrease behavioral performance in an ERP task. The findings obtained under this project highlight the magnitude of impairment experienced by night shift workers with SWD. These workers suffer from pathological sleepiness during overnight work hours, disrupted and inadequate sleep during the day (and, in some cases, during the night), and experience neurophysiologic changes due to sleep loss and circadian maladaptation that may lead to serious occupational hazards both to themselves and to the persons with which they interact during the night shift. Since so many night workers are employed in critical positions with grave consequences for error or lapses in judgment (e.g., protective services, transportation, healthcare, and energy), this study reinforces the notion that Shift Work Disorder represents a major occupational risk for public health and public safety. Fortunately, results from this study also indicate that certain adaptive behaviors are associated with a healthy circadian phase delay and non-pathological sleep and alertness. For example, properly timed light exposure and early-morning "compromised" bedtimes on days off from work were more likely to be found in the asymptomatic group than among workers with SWD. While more research is needed to translate these findings into an intervention trial, our results provide preliminary evidence that a circadian intervention for Shift Work Disorder may be able to prevent the condition and its deleterious consequences. [Description provided by NIOSH]
• Subjects:
  Behavior Biomarkers Circadian Rhythm Occupational Health Safety Shift Work Schedule Sleep Sleep Initiation And Maintenance Disorders
• Keywords:
  Circadian Rhythms Physiological Effects Shift Work Sleep Disorders Work Schedules
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report
• Place as Subject:
  Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-21
• NIOSHTIC Number:
  nn:20055570
• NTIS Accession Number:
  PB2019-100840
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, K01-OH-009996, 2014 Sep; :1-21
• Contact Point Address:
  Valentina Gumenyuk, PhD, 2799 West Grand Boulevard, CFP-351, Detroit, MI 48202
• Email:
  vgumeny1@hfhs.org
• Federal Fiscal Year:
  2014
• Performing Organization:
  Henry Ford Health System, Detroit, Michigan
• Peer Reviewed:
  False
• Start Date:
  20110901
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20140831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:972b69f88eb8ea1386b529ebdb12c46cef4692503597b628ab2d4ba5ba4587d80156e8d42294999c9c695f4e20752f57359aabeb17c50fd7754d72ec683ca24c
• Download URL:
  https://stacks.cdc.gov/view/cdc/218853/cdc_218853_DS1.pdf
• File Type:
  [PDF - 170.17 KB ]