Cancer agency declares night shift a potential carcinogen

There may be a real reason to call it the graveyard shift.

Working nights has been declared a “probable” cause of cancer by the International Agency for Research on Cancer, a part of the World Health Organization.

It’s estimated 20% of the labour force works nights — a phenomenon that most agree is here to stay.

Renee Ganter works 12 hour night shifts. She says by 4 am, her body is telling her it wants to sleep.

“About that time you start to feel cold, and very tired. We make sure there’s lots going on, we clean up, do paperwork, because if you sit too long, you’re going to fall asleep,” says Ganter.

Shift work is known to disrupt the natural sleep cycle and leaves many shift workers chronically tired.

But now, the health risks of working nights over the long term appear to be much more serious.

“When people stay up at night, and try to sleep in the day, there are increased risks of breast, colon and prostate cancer,” says Dr. Charles Eisler, of Brigham and Women’s Hospital.

No one knows exactly why, but it’s believed the hormone, melatonin, plays a key role.

“Exposure to light at night suppresses melatonin, which has a protective effect on the immune system, against certain cancers, and it also has an antioxidant effect,” says Moscovitch.

He says classifying night work as a “probable” carcinogen is an important policy move.

It raises awareness about the risks of not getting enough good quality sleep, which also include gastro-intestinal problems, high blood pressure and heart attacks.

It’s a wake up call, he says, for workers to take their sleep seriously.

“Making sure they get as much sleep as they can. In the day, make sure the sleeping environment is completely dark which help increases melatonin,” he adds.

Ganter says she worries about the cancer connection, but also worries about the bad habits she’s picked up while working nights. She admits to relying on high-carb foods and caffeine to help her burn the midnight oil.