Home-EEG assessment of possible compensatory mechanisms for sleep disruption in highly irregular shift workers - The ANCHOR study
Study objectivesWhile poor sleep quality has been related to increased risk of Alzheimers disease, long-time shift workers (maritime pilots) did not manifest evidence of early Alzheimers disease in a recent study. We explored two hypotheses of possible compensatory mechanisms for sleep disruption: Increased efficiency in generating deep sleep during workweeks (model 1) and rebound sleep during rest weeks (model 2). MethodsWe used data from ten male maritime pilots (mean age: 51.6{+/-}2.4 years) with a history of approximately 18 years of irregular shift work. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI). A single lead EEG-device was used to investigate sleep in the home/work environment, quantifying total sleep time (TST), deep sleep time (DST), and deep sleep time percentage (DST%). Using multilevel models, we studied the sleep architecture of maritime pilots over time, at the transition of a workweek to a rest week. ResultsMaritime pilots reported worse sleep quality in workweeks compared to rest weeks (PSQI=8.2{+/-}2.2 vs. 3.9{+/-}2.0; p<0.001). Model 1 showed a trend towards an increase in DST% of 0.6% per day during the workweek (p=0.08). Model 2 did not display an increase in DST% in the rest week (p=0.87). ConclusionsOur findings indicated that increased efficiency in generating deep sleep during workweeks is a more likely compensatory mechanism for sleep disruption in the maritime pilot cohort than rebound sleep during rest weeks. Compensatory mechanisms for poor sleep quality might mitigate sleep disruption-related risk of developing Alzheimers disease. These results should be used as a starting point for future studies including larger, more diverse populations of shift workers.