Couldn't find what you looking for?


Working night shifts long term has been established internationally as a probable cause of cancer. It is expected to become a basis for compensation claims to ACC.

Danish Government was the first to recognize the link between night shifts and cancer, paying compensation to 40 women who developed the disease after working night shifts in state sector jobs. Claims from those who had a family history of breast cancer have been rejected though.
The Danish move came after a United Nations health body concluded that working nights probably increased the risk of cancer.

After looking at studies of nurses, flight attendants and animals, The International Agency for Research on Cancer (IARC), categorized shift work the same as ultraviolet radiation, anabolic steroids and diesel engine exhausts in terms of cancer risk.

One study showed a 36 % greater risk of breast cancer for women who had worked night shifts for more than 30 years, compared with women who had never worked nights. This link was well proven in animal studies and there was "some evidence in humans". A 36 % increased risk doesn’t appear to be huge, however it should not be disregarded since breast cancer was the most common cancer in women.

The IARC report came out only in October 2007, so its implications were still being worked out internationally.

As with all occupational cancers, the aim should be to prevent breast cancer being caused by work hazards. However, very little is being done with the ones that are absolutely conclusively proven, let alone with new ones like this where the evidence is not yet conclusive.

This is something that should be definitely added to the list of known or probable causes of occupational cancer and just like the others on the list, someone might eventually make an ACC claim.

Among workers, 4 % of women and 10 % of men had worked a night shift - at least three hours between midnight and 5am - in the preceding four weeks.


Fortunately, most of us do not have to work night shifts. I think the next step would be to determine the physiological changes resulting from working night shifts that would predispose a person to cancer. Steps can then be taken to counteract these physiological changes.