Advancing the effective use of light for society and the environment.

Wednesday, April 26, 2006

Leading Scientists Examine the Impact of Architectural Lighting on Breast Cancer
By Mary Cimo
Seminar speakers
Left: Eva Schernhammer, Mark Rea, Julia Knight, John Bullough, Mariana Figueiro, Richard Stevens

Leading epidemiologists and lighting scientists gathered at Rensselaer Polytechnic Institute on April 17 to examine the impact of architectural lighting on breast cancer. Recent scientific studies claim to demonstrate a link between architectural lighting and cancer growth.

The panelists included Julia Knight, Ph.D., University of Toronto; Eva Schernhammer, MD, DrPH, Harvard Medical School; Richard Stevens, Ph.D., University of Connecticut Health Center; and Mariana Figueiro, Ph.D., Lighting Research Center at Rensselaer.  

“The incidence of breast cancer continues to grow, and the work of many epidemiologists and lighting scientists is leading us to believe that architectural lighting may be a factor,” said Mark Rea, Ph.D., director of the LRC and host of the panel discussion.

LRC researchers have developed a model that, for the first time, offers a framework for testing and exploring the practical aspects of architectural lighting and how it can affect human health. According to Rea, several scientific studies have determined that light on the eye’s retina is the primary synchronizer of human circadian rhythms, the biological cycles that repeat approximately every 24 hours. Researchers at the LRC are working to better understand and quantify light as a stimulus for the circadian system.

Nocturnal melatonin, a hormone, is used as a marker for the circadian clock. High levels are present at night when a person is in a dark environment, and low levels are present during the day with or without light. Scientific evidence suggests that disruption of the melatonin cycle may result in increased malignant tumor growth, as well as poor sleep quality, lack of alertness, seasonal depression, and immune deficiencies.

The new LRC model can be used as the foundation for a new system of circadian photometry, much like the current system of photometry based on human vision. Quantification of light as a stimulus for the circadian system has profound implications for exploring how lighting can be used to adjust our bodies’ clocks.

The panel discussion was moderated by John Bullough, Ph.D., Rensselaer adjunct assistant professor and LRC lighting scientist.

The event was Webcast live, and the video is archived on the event Web site.

More on the panelists

Dr. Stevens is a cancer epidemiologist at the University of Connecticut Health Center where he teaches and conducts research. One of his major research interests has focused on the confounding mystery of why breast cancer risk rises so dramatically as societies industrialize. He proposed in 1987 a radical new theory that the use of electric lighting, resulting in lighted nights, might produce "circadian disruption" causing changes in the hormones relevant to breast cancer risk. Accumulating evidence has generally supported the idea, and it has received wide scientific and public attention. His work has been featured on the covers of the popular weekly Science News and the scientific journal Cancer Research. Stevens spent 15 years at the U.S. Department of Energy's Pacific Northwest National Laboratory in Richland, Wash., before joining the UConn Health Center.

Dr. Knight is an associate professor in the Department of Public Health Sciences at the University of Toronto. The majority of her research is focused on understanding the etiology of breast cancer. She was a post-doctoral fellow and then a senior epidemiologist at Cancer Care Ontario. She later became an investigator at the Samuel Lunenfeld Research Institute of Mount Sinai Hospital. She earned a BSc degree in zoology from the University of Toronto and began graduate work in zoology before transferring to epidemiology, completing her MSc and Ph.D. in public health sciences.

Dr. Schernhammer is assistant professor of medicine at Harvard Medical School and associate epidemiologist at Brigham and Women's Hospital. Her primary research interest is exploring the exposures that influence the circadian system in humans. She has examined the effects of light at night on cancer risk through the melatonin pathway. She demonstrated that the effects of light at night may affect not only breast cancer, but also other cancers such as colorectal cancer, generating evidence that supports a new hypothesis on the development of cancer. Schernhammer has also conducted research measuring variations of the hormone melatonin in night-shift workers and its association with breast cancer risk.

Dr. Figueiro is an assistant professor at Rensselaer Polytechnic Institute and a program director at the LRC. Her research areas include photobiology, energy-efficient lighting, human factors in lighting, lighting applications, and working to better understand and quantify light as a stimulus for the circadian system. She has written numerous scientific articles for archival journals and trade publications and worked on the 9th edition of the Illuminating Engineering Society of North America Lighting Handbook. She also led the development of lighting design guidelines for older adults as outlined in the publication Lighting the Way: A Key to Independence, sponsored by the AARP Andrus Foundation.

About the LRC

The Lighting Research Center (LRC) is part of Rensselaer Polytechnic Institute and is the leading university-based research center devoted to lighting. Founded in 1988, the Lighting Research Center has built an international reputation as a trusted and reliable source for objective information about lighting technologies, applications, and products. Its mission is to advance the effective use of light and create a positive legacy of change for society and the environment.

Rennselear Polytechnic Institute