Research Mentor(s): Philip Cheng, Faculty
Research Mentor School/College/Department: Henry Ford Health System,
Presentation Date: Thursday, April 22, 2021
Session: Session 1 (10am-10:50am)
Breakout Room: Room 9
One crucial hurdle to the effective treatment of circadian misalignment in shift workers is a lack of knowledge about differences in circadian rhythms of workers with and without Shift Work Disorder (SWD). The objective of this study was to examine how circadian rhythms differed in SWD in order to help shift workers avoid developing sleep disorders as well as provide a stronger base for the development of successful treatments for those already diagnosed. We recruited 83 fixed night shift workers and examined melatonin profiles, circadian misalignment (Dim Light Melatonin Onset), and sleepiness profiles (Karolinska Sleepiness Scale). Melatonin profiles were determined and DLMO was assessed by means of 24 hourly saliva samples collected in dim light conditions (<10 lux). During these hourly collections, sleepiness was also measured using subjective patient judgment. Participants diagnosed with SWD on average secreted 26.6 pg/ml less melatonin from DLMO to DLMOffset than those without SWD. Further analysis also found that the amplitude of all participants' melatonin values amplitudes were significantly correlated with the amplitude of their sleepiness but not with average sleepiness. The correlation between melatonin and sleepiness was also comparable between the two groups, with both groups showing a 2 hour lag between subjective sleepiness and increases in melatonin. This study provides support that sleepiness in SWD is associated with changes in melatonin. Furthermore, it contributes new evidence that night shift workers with SWD secrete less melatonin on average than their counterparts while still experiencing increased symptoms of excessive sleepiness and other health problems.
Authors: Ali Abdalla, Philip Cheng
Research Method: Clinical Research