Abstract
Introduction
Shift work is increasingly common in our 24/7 society and can cause sleep disturbances and excessive sleepiness. Roughly 10-43% of shift workers are diagnosed with shift work disorder (SWD), characterized by excessive sleepiness accompanied by reduced sleep duration and/or insomnia. While more individuals work early morning shifts (shift start 3-6AM) compared to overnight shifts, few studies have investigated this population. The aim of this study was to characterize sleep in a population of early-morning shift workers.
Methods
We characterized sleep in early-morning shift workers (18-65yrs) from New England who were screened for a clinical trial of a wake-promoting agent. Pre-screening consisted of the Epworth Sleepiness Scale (ESS) and a Shift Work Disorder Questionnaire (SWD); screening consisted of the Pittsburg Sleep Quality Index Questionnaire Questionnaire (PSQI) ; a physical exam including an ECG, CBC, urinalysis, and comprehensive metabolic panel; a home sleep test (HST), a Monitored Wakefulness Test (MWT); a physician evaluation of their excessive sleepiness (Clinical Global Impression [CGI]); and a self-evaluation regarding how sleepiness affected their everyday life (Patient Global Impression [PGI]). Only data from consented individuals who met the initial inclusion criteria of being high risk for SWD were included in the analysis.
Results
158 early-morning shift workers met the pre-screening criteria and began the screening process. Most worked in retail, healthcare, maintenance, or transportation, and worked five shifts (65%) and 40+ hours (72%) per week, with a duration of 8.8±1.9 hours. 41 were screened out for abnormal findings on the PE, ECG, or screening blood/urine tests; 26 were screened out for previously un-diagnosed OSA or PLMD; 4 were ineligible for other reasons; 7 were excluded after their MWT due to long sleep latency, 20 were lost to follow-up/withdrew and 60 completed screening and met inclusion criteria. Their average (±sd) age was 37±11 years, 45% women, PSQI score 7.5±2.7, sleep duration 5.6±1.0, ESS=16.3±3.1, CGI=4.2±0.9, PGI=3.6±1.1.
Conclusion
Early-morning shift workers at an increased risk for SWD report short and disturbed sleep, excessive sleepiness, and a negative impact of sleepiness on their quality of life. Many have undiagnosed OSA and PLMD.
