Cancer patients' groups, researchers and trade unions are studying evidence of the link after Denmark's National Injuries Board approved compensation of up to DKr1m ($181,000, ?134,000, ?123,000) for 38 women who developed breast cancer after working one or more nights a week for at least 20 years.
A review of recent studies by the International Agency for Research on Cancer concluded that night work disrupted the body's circadian rhythms, inhibiting the production of melatonin, a hormone important in fighting cancer. “Shift work that involves circadian disruption is probably carcinogenic to humans,” it concluded, putting the risk at the same level as chemicals containing lead, anabolic steroids, creosote, diesel exhaust and sun lamps.
Ahead of the full IARC findings to be published later this year, Australia's National Breast and Ovarian Cancer Centre cautioned that some studies indicated a “small increase in breast cancer risk . . . in limited groups of women . . . after 20 years or more of shift work”, findings were inconsistent and some “open to questions of bias and confounding”.
But Grete Christensen, deputy president of the Danish Nurses' Organisation, seven of whose members won compensation, said: “Now you can be compensated for working night shifts just as if you were working with poisonous chemicals in some factory.”
Other European countries including the Netherlands, Belgium and the UK are also examining looking at the link between night work and breast cancer and may move to granting compensation.
The Cancer Society of Finland said a forthcoming study on work and cancer in Nordic countries would add to the evidence of a link between shift work and breast cancer in both men and women.
芬蘭癌症協會(Cancer Society of Finland)表示，一份研究北歐國家工作與癌症關係的報告即將發表，將提供更多證據，說明輪班工作與乳癌之間存在關聯，不管是男性還是女性。
Up to a fifth of employees in Europe and the US work shifts including nights. More than 30 per cent work at night in healthcare, manufacturing, mining, transport, communication and the leisure and hospitality sectors.
“There is sufficient evidence that night work is causing damage to men's and women's health,” says Laurent Vogel, director of the health and safety department of the European Trade Union Confederation's Institute. “The point is to limit night work to social or technical reasons . . . [not] just for reasons of profitability.”
Denmark's injuries board looked at 75 cases last year and approved compensation in 38. The board said it might recognise night working as an occupational disease once the full IARC report was published, speeding up approval of pay-outs.
The board's decision has already prompted some Danish employers to change policy. SAS, the leading Scandinavian airline, took action when one of its Danish stewardesses won compensation for developing breast cancer after more than 20 years of long-haul flights. “We have given our crew members the option of not flying long haul if they are not comfortable doing that,” SAS said.