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.

Related Articles


"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 October 24, 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 October 24, 2014).

Share This



More Health & Medicine News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com
Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Despite Rising Death Toll, Many Survive Ebola

Despite Rising Death Toll, Many Survive Ebola

AP (Oct. 23, 2014) The family of a Dallas nurse infected with Ebola in the US says doctors can no longer detect the virus in her. Despite the mounting death toll in West Africa, there are survivors there too. (Oct. 23) Video provided by AP
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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