The association between shift work-related sleep complaints and shift work intolerance

Previous studies have revealed the negative consequences of shift work in some individuals, with others better tolerating shift work. The present study investigated clinical implications of shift work-related sleep complaints as a manifestation of shift-work intolerance. Responses were obtained from 923 shift workers and 850 non-shift workers at Seoul National University Bundang Hospital in Seongnam, Korea. The self-reported questionnaires were administered to assess demographic and clinical factors of the participants. Shift work-related sleep complaints were defined as complaints of insomnia or excessive sleepiness related to shift work schedule. Shift workers with sleep complaints suffered from more severe fatigue, depression, anxiety and impaired quality of life compared with both non-shift workers and shift workers without sleep complaints (all p<0.05). However, we found no substantial difference in clinical symptoms between non-shift workers and shift workers without sleep complaints. The associated factors of shift work-related sleep complaints were frequent night shifts (OR=1.09, 95% CI=1.02-1.15), evening chronotype (OR=0.97, 95% CI=0.95-0.99) and resilience (OR=0.98, 95% CI=0.97-0.99). Shift workers with sleep complaints can suffer from more severe adverse effects of shift work compared to non-shift workers and shift workers without sleep problems. This study suggests that shift-work-related sleep complaints might be a manifestation of shift work intolerance. Therefore, physicians need to recognize and modify the associated factors with sleep complaints alleviating shift work-related health burden.