Breast cancer link to working nights: Three late shifts a week ‘doubles the risk of disease’

By
Jenny Hope

17:38 EST, 28 May 2012

|

21:54 EST, 28 May 2012

Women who work night shifts are at higher risk of breast cancer, warn researchers.

Their findings suggest working at night increases the chances of the disease by 40 per cent.

Women working more than two night shifts a week have double the risk of those on day shifts, says a report from scientists, while night workers who also describe themselves as ‘morning people’ or ‘larks’ have a stronger risk than those who say they are ‘night owls’.

New research is suggesting that a hormone that suppresses tumours in the body may be disrupted by constant exposure to light during night-time hours

New research is suggesting that a hormone that suppresses tumours in the body may be disrupted by constant exposure to light during night-time hours

Experts believe a hormone in the body that potentially suppresses tumours may be disrupted by constant exposure to light during night-time hours.

There has been mounting evidence that night shifts might boost cancer risk because of the disruption to the body clock and hormone production.

The latest study, backed by the Danish Cancer Society, involved more than 18,500 women working for the Danish army between 1964 and 1999.

Researchers were able to contact 210 women out of a total of 218 who had breast cancer between 1990 and 2003 and who were still alive in 2005/06.

These women were matched with 899 women of the same age who had also worked for the Danish army but had not developed breast cancer.

The women completed a detailed questionnaire which included questions on their working patterns, use of the Pill and HRT, sunbathing habits and whether they classified themselves as a ‘morning’ or ‘evening’ person.

Overall, night shift work was linked with a 40 per cent increased risk of breast cancer compared with no night shifts. But women who had worked night shifts at least three times a week for at least six years were more than twice as likely to have contracted the disease as those who had not.

Those working this shift pattern for this length of time were even more likely to develop breast cancer if they were ‘morning’ types, says a report in the journal Occupational and Environmental Medicine.

They were almost four times as likely to have the disease as those who worked no night shifts, possibly because they are more susceptible to body clock disruption.

Researcher Johnni Hansen said the findings suggested that working up to two nights a week was not long enough to disrupt the body clock.

But frequent night shifts for several years may disrupt circadian rhythms – the body clock – and sleep patterns.

Night shift workers, such as the emergency services, have double the risk risk of breast cancer, new research suggests

Night shift workers, such as the emergency services, have double the risk risk of breast cancer, new research suggests

Exposure to light at night inhibits production of melatonin, which is produced by the pineal gland in the brain between the hours of 9pm and 8am. Melatonin, a hormone which dictates the natural cycles that govern sleep patterns, helps suppress tumours.

Research suggests that unusually low levels of melatonin, which are seen in people exposed to light during the night, may promote tumour growth.

Dr Rachel Greig, of the charity Breakthrough Breast Cancer, said: ‘It may be that night shifts themselves are not the only cause, as shift work can increase the likelihood of other lifestyle risk  factors, such as lack of exercise.

‘All women should cut back on alcohol, get regular physical activity and maintain a healthy diet to reduce their risk of breast cancer.’

Here’s what other readers have said. Why not add your thoughts,
or debate this issue live on our message boards.

The comments below have not been moderated.

What a bunch of nonsense. My mum worked night shifts for years because of the higher pay when she was a nurse – if she gets diagnosed with breast cancer can she sue the NHS for dangerous working conditions?!

I worked nights for 7 years…i had to leave and get a day job as it was making me ill i had loads of health problems….after 4 months working days and sleeping when i should all my health problems went away….and i can tell you the amount of women i knew who i worked with were all in the same boat ….i remember bumping into a woman i use to work nights with she looked shocking she was struggling with her health….she did say to me god you look a 100 times better and i told her i felt it ….she too was wanting to come off nights and go on days….i do think nights doesnt suit everyone and it can make you ill…

Do people actualloy get paid to come up with all these ideas?

Utter rubbish it really annoys me that these idiots get paid for guess work

I’ve never worked night shifts, eat a healthy diet, never smoked was a normal size 10 not fat or obese, walked my dogs every day, and before being diagnosed went to the gym 3/4 times a week, had my children young and breastfed all of them, a text book case for not getting breast cancer. I had the tumour for about 1 1/2 yrs, it didn’t show a lump but was picked up on the national screening when i turned fifty. My Macmillan Nurse did ask me if I was under stress at that tome there seems to be some believe that we all have the cancer gene which can explode at any time and stress can be a factor. I was under the doctor for stress and depression at about that time as I was being bullied by my boss, after about 8 months i managed to change jobs in same company. HR were very understanding as there had been complaints about him before. But unfortunately I am now on long term sick leave fighting this disease as the cancer has spread because I had had it for so long.

Ever more theories without foundation,it’s all fear indoctrination.

I worked night shifts for 8 years, one week of nights then a week off consistently. The last 4 years I was constantly ill will kidney infections, colds and headaches ect. I also had a young (under 5) daughter to look after during the day when my husband was at work. Nightmare time, I benefitted so much health wise when I quit work to become a full time mother when my second child came along. Tiredness is the worst feeling and working night shift hours are a nightmare for the body to be dealing with.

During the 1960s I worked three night shifts per week but I suppose now I was lucky enough to have avoided this dreaded disease.

No idea of what might be the cause…but I undertook night-shift for about 2 years, 3 times a week, and it totally drained me. Your body clock is entirely wrecked…in the event you cannot get to sleep, going off shift at 8.30 or 9.00am…you are facing a real melt-down, if you then have to turn up the next evening for your next night shift.

This is really important and well established research now employers and employees should be taking into account. Wonder whether women will be suing employers in years to come?

The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline.

You can skip to the end and leave a response. Pinging is currently not allowed.

Leave a Reply

Powered by WordPress | Designed by: Premium WordPress Themes | Thanks to Themes Gallery, Bromoney and Wordpress Themes