Stories tagged night shift work

Dec
07
2007

Does anybody really know what time it is?: More data is connecting overnight work shifts with higher risks for getting cancer. The mounting evidence may add the night shift to the list of possible cancer causers.
Does anybody really know what time it is?: More data is connecting overnight work shifts with higher risks for getting cancer. The mounting evidence may add the night shift to the list of possible cancer causers.Courtesy Leo Reynolds
Several health agencies are close to adding working the graveyard shift to the list of things that can increase your risk of getting cancer.

That sounds pretty wild compared to the direct intake of harmful chemicals that other cancer-causers usually involve. But looking a little farther into the matter, the connections don’t seem so weak.

Here’s what’s at issue with the overnight work: being active and doing work during the darkest hours of the day messes up the body’s circadian rhythm, which is the fancy-pants term for body’s biological clock. It’s during the night, and a typical night of sleep, that our bodies create a hormone called melatonin, which can act against the formation of tumors.

There is growing research backing up this theory. Several studies have found that women working the over-night shift are more prone to get breast cancer. Men working the same shifts have higher incidences of prostate cancer. Experiments with animals who are shifted out of their normal day/night routines have found that they develop more tumors and die earlier, on average.

Along with the risks of having their bodies producing less melatonin, lack of sleep could be another stressor on the body that could lead to cancer, researchers note. A deficiency of sleep can weaken a body’s immune system and make it more vulnerable to cancer-causing agents.

There still are skeptics, of course, and researchers are quick to note that what they’ve learned so far doesn’t prove that working overnight can cause cancer. But there is enough evidence to give them reason to keep probing and find out what other connections there might be to working late and cancer risk.

So what do you think? Share your ideas on over-night work and cancer risks here with other Science Buzz readers.