38 women have been compensated for developing cancer on the job
Employers in Denmark are beginning to compensate women who have developed breast cancer after working night shifts.
So far, 38 Danish women have receive payments through their employers' insurance companies, according to the Danish National Board of Industrial Injuries.
To qualify for payments, a woman must have developed breast cancer after having worked at least one night shift a week for 20 to 30 years.
The World Health Organization's International Agency for Research on Cancer classified night work as a probable carcinogen, on the same level as UV rays, in 2007 after a scientific review found long-term night workers have an increased risk of breast cancer.
Scientists suspect overnight work is dangerous because it disrupts the circadian rhythm — the body's biological clock.
The hormone melatonin, which can suppress tumour development, is usually produced at night. Light shuts down melatonin production, so people working in artificial light at night may have lower melatonin levels.
Experts estimate that nearly 20 per cent of the working population in developed countries work the night shift.