It’s now well established that people who work the night shift have an increased risk of getting sick. Washington State University Medicine Prof. Hans Van Dongen says that may also mean a higher susceptability to cancer. Van Dongen collaborated with Siobhan Gaddameedhi, a cancer specialist and former WSU Pharmacy researcher now at North Carolina State. Their mission: find out what happens in shift workers that makes them more susceptible to cancer.
They brought 14 volunteers to the sleep lab on the WSU Spokane campus. Half completed a three-day simulated day shift schedule, the other half had a three-day night schedule. Then, Van Dongen says, they were kept awake and monitored for a full day.
“People were in dentist-like chairs, sort of semi-recumbent, for the full 24 hours," he said.
They were fed snacks and drinks every hour. They were kept awake and in constant light the whole time. The study team members drew blood from the participants every two hours. Van Dongen says they used new technology to analyze the blood and measure the body’s rhythms.
“Rhythms in your heart. Rhythms in your brain. But also rhythms in your cells and rhythms in your metabolism," he said.
Van Dongen’s team monitored 800 individual genes, including some of those that repair DNA damage within cells.
“We noticed in those genes in the night workers that those genes were not as rhythmic as they were in the day workers. There was something wrong with the timing of those rhythms. That gave us the first clue that something was wrong, that we might be looking at a problem of DNA damage in the night workers," he said.
He says, if that damage isn’t fixed in a timely manner, it could mean trouble.
“So you get a build up of impairment of DNA damage and that can ultimately lead to genomic instability and when you have genomic instability, that’s when cancer starts to occur," Van Dongen said.
The next step, he says, is to study this in real shift workers and see if the results are replicated. Then there may be work over the next several years to figure out preventive measures that lower the risk of health damage for people who work non-traditional hours.