Light Pollution and Your Health

Artificial home lighting may increase breast cancer rates

Exposure to frequent artificial light at night appears to increase the breast cancer risk among women in their homes, according to an analysis by a Long Island researcher.

Study: Light at Night is Dangerous to Health 

Night life under electric lighting may cause serious behavioral disorders and physical diseases including cancer, according to a specialist team led by Professor N.N. Pertov Scientific Research Institute of Oncology, Russian Ministry of Healthcare

Light 'risk' to premature babies 

Constant exposure to artificial hospital lighting may damage the development of premature babies' biological clocks, research suggests. (ed: yet another example of how little we really know about light)

Ocular Input for Human Melatonin Regulation:
Relevance to Breast Cancer 

The impact of breast cancer on women across the world has been extensive and severe. As prevalence of breast cancer is greatest in industrialized regions, exposure to light at night has been proposed as a potential risk factor. This theory is supported by the epidemiological observations of decreased breast cancer in blind women and increased breast cancer in women who do shift-work.

Today Show: Light-Cancer Link

An interview with the editor of Prevention Magazine... discussing their recent article linking Light Pollution and various forms of Cancer. (Requires MS Internet Explorer or Real Player to view)

Bright Lights, Big Cancer  

Another article, this time in Science News, discusses the growing link between night time illumination... and certain forms of cancer. "Light at night is now clearly a risk factor for breast cancer," David E. Blask of the Bassett Research Institute in Cooperstown, N.Y  says. "Breast tumors are awake during the day, and melatonin puts them to sleep at night." Add artificial light to the night environment, and "cancer cells become insomniacs"

The Light-Cancer Connection  

Exposure to light at night appears to raise the risk of several types of cancer... Simply put, light at night snuffs out one of the body's most powerful anticancer crusaders, a hormone called melatonin. 

Light pollution as a risk factor for breast cancer: a GIS-assisted case study

A positive association was found between night light intensity measured by satellite and breast cancer rates in towns.

Abnormally high cancer rates were found along the 'seam lines' where extensive intense security lighting is in use.  Abnormally low cancer incidence rates were found in low-income areas where outdoor and indoor artificial illumination is dimmer than elsewhere for economic reasons.  For these two groups combined, the rate of breast cancer incidence was highly correlated with in-situ measures of illuminance at night.

Melatonin-Depleted Blood from Premenopausal Women Exposed to Light at Night Stimulates Growth of Human Breast Cancer

The increased breast cancer risk in female night shift workers has been postulated to result from the suppression of pineal melatonin production by exposure to light at night. Exposure of rats bearing rat hepatomas or human breast cancer xenografts to increasing intensities of white fluorescent light during each 12-hour dark phase (0-345 µW/cm²) resulted in a dose-dependent suppression of nocturnal melatonin blood levels and a stimulation of tumor growth

American Association for Cancer Research  

 "These results are the first to show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night."

Night-shift women face cancer risk

Women who work night shifts are more likely to get breast cancer... due to suppressed melatonin production... from exposure to light at night.