Most people may believe that working night shifts is safe and harmless, and would consider it to be completely normal.

However, research has shown otherwise.

Almost 40 women are being awarded <a rel="nofollow" onclick="javascript:pageTracker._trackPageview('/outgoing/article_exit_link');" href=" ">compensation</a> by the Danish government after they developed breast cancer when working night shifts.

Increased risk of cancer for night shift workers
According to research by the International Agency for Research on Cancer (IARC) based in France, women working night shifts were more likely to develop breast cancer.

The research had been conducted as part of an investigation after statistics showed that work illness involving cancer had increased.

The research, which was concluded in 2007, found that the “circadian disruption” of sleep amongst nurses and flight attendants could increase the risk of developing cancer.

Animal studies had revealed that the development of a tumour was increased through constant light, simulated jet lag and dim light at night.

According to a review by IARC, women who had spent 30 days working night shifts had a higher risk of developing breast cancer than those who had not worked any nights.

It stated that those working nights had a 36 per cent higher chance of developing the cancer than those who had not.

US studies have also revealed that there was a 50 per cent increase in breast cancer for night shift workers.

The finding of the study by IARC has now led the Danish government to compensate female employees who suffered with the cancer.

Ulla Mahnkopf worked as a flight attendant for 30 years before she developed breast cancer.

She said: “It's not just the surgery but all the thoughts - do I survive this? I had bilateral cancer so not just one breast, two breasts.”

John Osmond, chief medical officer for the Health and Safety Executive (HSE) said: “The HSE has been very on the ball in this area and has commissioned a very eminent epidemiologist to examine the risk of working at night and whether there is any link to breast cancer. This report will be completed in 2011.”

However, there are a number of other dangers related to working at night.

Increased risk of work accidents
A study conducted in 2003 found that fatigue is a major risk factor linked to sustaining a personal injury from an <a rel="nofollow" onclick="javascript:pageTracker._trackPageview('/outgoing/article_exit_link');" href=" ">accident at work</a>.

Such injuries involve not only nurses and flight attendants, but also those working in environments which involve the use of machinery.

Cab drivers and other vehicle drivers are also more likely to have a <a rel="nofollow" onclick="javascript:pageTracker._trackPageview('/outgoing/article_exit_link');" href=" /">car accident</a> due to fatigue when working on a night shift.