Night shift workers and cancer risk: Researchers find new clues

Spokane, WA — Night shift schedules “throw off the timing of expression of cancer-related genes in a way that reduces the effectiveness of the body’s DNA repair processes when they are most needed,” results of a recent study led by researchers from Washington State University show.

Jason McDermott, a computational scientist with the Pacific Northwest National Laboratory’s Biological Sciences Division, and others conducted a simulated shift work experiment involving 14 young adults. Half of the participants followed a night shift schedule for three days, while the other half completed a day shift schedule.

Analyses of blood samples taken from the participants show that their white blood cells featured different rhythms of many of the cancer-related genes when compared between the two groups. In particular, genes related to DNA repair “lost their rhythmicity” under the night shift condition, whereas “distinct rhythms” appeared under the day shift condition.

Additionally, the white blood cells of the night shift group showed more evidence of DNA damage. When analyzed at two different times of the day, the cells of the night shift group showed an increase in DNA damage in the evening when compared with the day shift participants. This means, the researchers note in a press release, that the cells from the night shift group were more vulnerable to external damage from radiation – a known risk factor for DNA damage and cancer. The researchers say their next step is to conduct the same experiment with real-world night shift workers to determine whether unrepaired DNA damage builds up over time, which, if proven true, could be used as the basis for prevention strategies.

“It is high time that we find diagnosis and treatment solutions for this underserved group of essential workers so that the medical community can address their unique health challenges,” Hans Van Dongen, a professor in the WSU Elson S. Floyd College of Medicine and director of the WSU Sleep and Performance Research Center, said in the release.

The study was published online in the Journal of Pineal Research.