According to the researchers, consumers can increase their risk for cancer when their body’s internal clock has days and nights consistently reversed. They explained that when the circadian rhythm is disrupted from its natural cycle, it damages consumers’ white blood cell DNA expression. This puts night shift workers at a higher risk of developing cancer.
“There has been mounting evidence that cancer is more prevalent in night-shift workers, which led the World Health Organization’s (WHO’s) International Agency for Research on Cancer to classify night shift work as a problematic carcinogenic,” said researcher Shobhan Gaddameedhi. “However, it has been unclear why night shift work elevates cancer risk, which our study sought to address.”
Circadian rhythm disruptions lead to genetic damages
To understand how night shift work can impact consumers’ health, the researchers had 14 participants stay in a sleep lab for one week. Half of the group spent three days on a day shift schedule while the other half spent three days on a night shift schedule.
The researchers analyzed blood samples collected from the participants during the study period and observed that those on the simulated night shift had significant differences in their white blood cells than those on the day shift schedule.
The researchers explained that while the body has its own 24-hour circadian rhythm, individual cells throughout the body also operate on their own internal clocks. Their work revealed that disrupting the body’s natural biological clock by being awake during traditional sleeping hours also disrupted the white blood cells’ biological clocks. Operating on a night shift schedule left the white blood cells with more structural DNA damage, which is what increases the risk of cancer.
“Taken together, these findings suggest that 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,” said researcher Jason McDermott.
The researchers’ next step is to see if these findings hold up in a trial of actual night shift workers. If they do, the goal would be to develop potential treatments that could be targeted to night shift workers to protect their long-term health.
“Night shift workers face considerable health disparities, ranging from increased risks of metabolic and cardiovascular disease to mental health disorders and cancer,” said researcher Hans Van Dongen. “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.”