Featured Research

from universities, journals, and other organizations

Night work may put women's health at risk

Date:
June 19, 2012
Source:
INSERM (Institut national de la santé et de la recherche médicale)
Summary:
The risk of developing breast cancer is higher among women who have worked at night, according to new research. The study compared the careers of 1,200 women who had developed breast cancer between 2005 and 2008 with the careers of 1,300 other women.

The results of a study carried out by the researchers of the Inserm unit 1018 (Centre for research in Epidemiology and Population Health) and published in the International Journal of Cancer show that the risk of developing breast cancer is higher among women who have worked at night. The study, carried out in France and named the CECILE study, compared the careers of 1200 women who had developed breast cancer between 2005 and 2008 with the careers of 1300 other women.

Breast cancer is the number one cause of female mortality. It affects 100 out of 100,000 women per year in developed countries. Each year, more than 1.3 million new cases are diagnosed, 53,000 of these in France.

The risk factors of breast cancer are varied. They include genetic mutations, late first pregnancy, low parity or hormone therapy, but other causes of breast cancer such as way of life, environmental or professional causes have not yet been completely identified.

In 2010, based on experimental and epidemiological work, the International Agency for Research on Cancer (IARC) classified work that disturbed the circadian rhythm as being "probably carcinogenic." The circadian rhythm, that regulates the alternation between wakefulness and sleep, controls numerous biological functions and is altered in people who work at night or who have disrupted working hours. Several hypotheses have been put forward to explain the observed links between night work and breast cancer: exposure to light during the night, that eliminates the nocturnal melatonin surge and its anti-carcinogenic effects, disturbed functioning of the biological clock genes that control cell proliferation, or sleep disorders that can weaken the immune system.

So the Inserm researchers examined the effect of night work on the health of women in a major population study carried out in France between 2005 and 2008. The careers of 3000 women were examined, including each period of night work. In total, over 11% of women had worked nights at some time during their career.

The risk of developing breast cancer was 30% higher in women who had worked nights compared to women who had never worked nights. This increased risk was particularly marked in women who had worked nights for over four years, or in women whose working rhythm was less than 3 nights per week, because this led to more frequent disturbances between night and day rhythms.

Finally, the link between night work and breast cancer seemed to be more marked when we looked at women who had worked at night prior to a first pregnancy. An explanation for this result could be that the mammary cells, incompletely differentiated in women before their first pregnancy, are more vulnerable.

"Our work has corroborated the results of previous studies and poses the problem of taking night work into consideration in public health management, especially since the number of women working atypical hours is on the increase", states Pascal Guénel, the main author of this work.


Story Source:

The above story is based on materials provided by INSERM (Institut national de la santé et de la recherche médicale). Note: Materials may be edited for content and length.


Journal Reference:

  1. Florence Menegaux, Thérèse Truong, Antoinette Anger, Emilie Cordina-Duverger, Farida Lamkarkach, Patrick Arveux, Pierre Kerbrat, Joëlle Févotte, Pascal Guénel. Night work and breast cancer: A population-based case-control study in France (the CECILE study). International Journal of Cancer, 2012; DOI: 10.1002/ijc.27669

Cite This Page:

INSERM (Institut national de la santé et de la recherche médicale). "Night work may put women's health at risk." ScienceDaily. ScienceDaily, 19 June 2012. <www.sciencedaily.com/releases/2012/06/120619112907.htm>.
INSERM (Institut national de la santé et de la recherche médicale). (2012, June 19). Night work may put women's health at risk. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/06/120619112907.htm
INSERM (Institut national de la santé et de la recherche médicale). "Night work may put women's health at risk." ScienceDaily. www.sciencedaily.com/releases/2012/06/120619112907.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) — Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) — At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) — The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:  

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile iPhone Android Web
      Follow Facebook Twitter Google+
      Subscribe RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins