Does Your Shift at Work Put You at a Greater Risk for Developing Cancer?

Apr 03, 2009

Does your shift at work put you at a greater risk for developing cancer?

The answer may surprise you in that studies are finding that late-night exposure to light may diminish levels of a natural cancer-fighting hormone.


Dr. David Blask, professor of the practice in the Tulane University School of Medicine Department of Structural and Cellular Biology, is a widely acclaimed expert on cancer biology, circadian rhythms and the health implications of exposure to light. In the early 1980s, Blask was one of only a handful of scientists studying regulation of development and growth by , a hormone produced by the pineal gland during sleep in the darkness of night. Melatonin modulates many of the body’s natural circadian rhythms, including the sleep/wake cycle, and has been shown to have important anti-cancer properties.

He was the first to demonstrate that nighttime doses of melatonin suppress human breast cancer cell growth. He has become a world-renowned expert on the negative health implications and increased cancer risk associated with melatonin suppression due to exposure to light at night.

Using specially designed photoperiodic chambers, which allow precise control over light exposure at night, he and his research team have demonstated that manipulating light intensity at night, and thus melatonin production, dramatically affects human breast cancers growing in rats. Their experiments show that reduced levels of melatonin coupled with higher levels of light at night boosted human breast cancer tumor growth in rats.

This landmark research helped to lay the groundwork for a scientific working group (of which Blask was a member) appointed by the World Health Organization to add shift work and exposure to light at night to its list of possible carcinogens. Shift workers have been shown to have higher risks for breast, prostate and other cancers.

Blask has advised Congressional staffers on the implications of light pollution on the environment as part of an effort to get the Environmental Protection Agency to address the problem.

Provided by Tulane University

Explore further: Survival differences seen for advanced-stage laryngeal cancer

add to favorites email to friend print save as pdf

Related Stories

Nightime light linked to cancer

Feb 21, 2008

An Israeli study said women who live in well-lighted neighborhoods are more likely to develop breast cancer than those who live in darker areas.

Another grape excuse to hit the bottle

Jun 16, 2006

Scientists in Italy say they have discovered that the grapes used to make some of the most popular red wines contain high levels of the sleep hormone melatonin.

Circadian math: 1 plus 1 doesn't always equal 2

Jun 07, 2008

Like a wristwatch that needs to be wound daily for accurate time-telling, the human circadian system — the biological cycles that repeat approximately every 24 hours — requires daily light exposure to ...

Recommended for you

Survival differences seen for advanced-stage laryngeal cancer

23 hours ago

The five-year survival rate for advanced-stage laryngeal cancer was higher than national levels in a small study at a single academic center performing a high rate of surgical therapy, including a total laryngectomy (removal ...

Gene test aids cancer profile

Nov 27, 2014

The first round of chemotherapy did little to suppress Ron Bose's leukemia. The second round, with 10 times the dose, knocked the proliferating blast cells down, but only by half.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.