Featured Research

from universities, journals, and other organizations

Connection between light at night and cancer suggested by new study

Date:
September 2, 2010
Source:
University of Haifa
Summary:
A recent study by researchers in Israel has found a new link between light at night and cancer.

A recent study from the Center for Interdisciplinary Chronobiological Research at the University of Haifa has found a new link between light at night (LAN) and cancer. The research joins a series of earlier studies carried out at the University of Haifa that also pointed to the correlation.

"High power light bulbs contribute more to 'environmental light pollution', which the study has shown is a carcinogenic pollution," notes Prof. Abraham Haim, who headed the study, published in the journal Sleep Science.

Earlier studies in which Prof. Haim has participated at the University of Haifa have shown that people living in areas that have more night-time illumination are more susceptible to prostate cancer in men and breast cancer in women. The researchers' hypothesis was that LAN harms production of melatonin, a hormone that is released from the pineal gland during the dark part of the 24-hour cycle and which is linked to the body's cyclical night-day activity and seasonality. When this hormone is suppressed, the occurrence of cancer rises.

The current study, in which Dr. Fuad Fares and Adina Yokler, Orna Harel and Hagit Schwimmer also participated, set out to establish or refute this hypothesis. In order to do so, four groups of lab mice injected with cancerous cells were examined: one group was exposed to "long days" of 16 hours of light and 8 hours of darkness, simulating exposure to artificial light beyond the natural number of light hours in a day; a second group was exposed to the same "long days" but were treated with melatonin; a third group was exposed to "short days" of 8 light hours and 16 dark hours; and a fourth group was exposed to the same "short days" but during the dark hours was exposed to a half-hour interval of light.

The results demonstrated a link between LAN and cancer: the cancerous growths in mice exposed to "short days" were smallest (0.85 cubic centimeters on average), while those mice exposed to the interval of LAN during dark hours had larger growths (1.84 cubic cm average) and those exposed to "long days" even larger growths (5.92 cubic cm average).

The study also demonstrated that suppression of melatonin influences development of the tumor. The size of tumor in mice exposed to "long days" but treated with melatonin was only 0.62 cubic cm on average, which is not much different from the size of the growth in mice exposed to "short days." The study also found that the death rate in mice treated with melatonin was significantly lower than in those not treated.

The researchers say that their study results show that suppression of melatonin due to exposure to LAN is linked to the worrying rise in the number of cancer patients over the past few years. However, it is not yet clear what mechanism causes this.

"Exposure to LAN disrupts our biological clock and affects the cyclical rhythm that has developed over hundreds of millions of evolutionary years that were devoid of LAN. Light pollution as an environmental problem is gaining awareness around the world, and the World Health Organization's International Agency for Research on Cancer (IARC) has already classified working the night shift as a higher grade of cancer risk," the researchers noted.


Story Source:

The above story is based on materials provided by University of Haifa. Note: Materials may be edited for content and length.


Journal Reference:

  1. Abraham Haim, Adina Yukler, Orna Harel, Hagit Schwimmer, Fuad Fares. Effects of chronobiology on prostate cancer cells growth in vivo. Sleep Science, 2010; 3 (1): 32-35 [link]

Cite This Page:

University of Haifa. "Connection between light at night and cancer suggested by new study." ScienceDaily. ScienceDaily, 2 September 2010. <www.sciencedaily.com/releases/2010/09/100902101625.htm>.
University of Haifa. (2010, September 2). Connection between light at night and cancer suggested by new study. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2010/09/100902101625.htm
University of Haifa. "Connection between light at night and cancer suggested by new study." ScienceDaily. www.sciencedaily.com/releases/2010/09/100902101625.htm (accessed September 16, 2014).

Share This



More Health & Medicine News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Study Links Male-Pattern Baldness To Prostate Cancer

Study Links Male-Pattern Baldness To Prostate Cancer

Newsy (Sep. 16, 2014) New findings suggest men with a certain type of baldness at age 45 are 39 percent more likely to develop aggressive prostate cancer. 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