Health Impacts

of Light Pollution

The mounting studies focusing on the impact of night time lighting is becoming an ominous drumbeat of disturbing news.  Blind women are 40% less likely to get breast cancer that all sighted women.  In developing countries (without much night time lighting), 1 in 35 women will develop breast cancer.  In the industrialized world, 1 in 7 women will develop breast cancer.  And for those women working on night shifts, their risk doubles or triples.   

 

Breast and Prostate Cancer

 

Recent studies of shift-working women have reported that excessive exposure to light at night (LAN) may be a risk factor for breast cancer. However, no studies have yet attempted to examine the co-distribution of LAN and breast cancer incidence on a population level with the goal to assess the coherence of these earlier findings with population trends. Nighttime satellite images were used to estimate LAN levels in 147 communities in Israel.

 

Multiple regression analysis was performed to investigate the association between LAN and breast cancer incidence rates and, as a test of the specificity of our method, lung cancer incidence rates in women across localities under the prediction of a link with breast cancer but not lung cancer. After adjusting for several variables available on a population level, such as ethnic makeup, birth rate, population density, and local income level, a strong positive association between LAN intensity and breast cancer rate was revealed (p<0.05), and this association strengthened (p<0.01) when only statistically significant factors were filtered out by stepwise regression analysis. Concurrently, no association was found between LAN intensity and lung cancer rate. These results provide coherence of the previously reported case-control and cohort studies with the co-distribution of LAN and breast cancer on a population basis. The analysis yielded an estimated 73% higher breast cancer incidence in the highest LAN exposed communities compared

 

Melatonin Suppression

 

The American Medical Association in 2009 passed a resolution that recognizes a host of problems with light pollution, including health issues—such as breast cancer—that are “associated with human eye exposure to light at night.”   The AMA resolution (view it in full below) explains that the increasing amount of light in the world, including streetlight glare and intrusive light that “trespasses” into bedroom windows and homes, is linked to higher rates of cancer and other human health problems. It reduces the production of melatonin, a hormone that helps regulate sleep cycles, and hampers the immune system, the group says. Too much night light hurts wildlife, as well.

 

As the AMA puts it: “Light trespass has been implicated in disruption of the human and animal circadian rhythm, and strongly suspected as an etiology of suppressed melatonin production, depressed immune systems, and increase in cancer rates such as breast cancers.” In addition, it “disrupts nocturnal animal activity and results in diminished various animal populations’ survival and health.”

 

Professor Charles Czeisler of the Harvard Medical School recently stated in Science magazine that “If light was a drug the government wouldn’t approve it.”       docs.darksky.org/Docs/AMA%20Light%20pollution.pdf

 

 

For more information see:

www.muskokaheritage.org/ecology-night/media/steven-lockley.pdf

docs.darksky.org/Docs/ida_human-health_brochure.pdf

 

Carbon Tax Cheaper When Compared to Health Costs Saved

 

Shifting away from fossil fuels helps cut down on other, more conventional pollutants that cause all sorts of medical problems: SO2 and NOx and mercury and particulates. And how much is that worth? That's what a new study from Gregory Nemet, Tracey Holloway, and Paul Meier at the University of Wisconsin-Madison tried to figure out. The researchers surveyed 48 studies on the subject and found that, while estimates of the health benefits can vary quite a bit, they average $44 per ton of CO2 in wealthy countries and $81/ton in developing countries. That's bigger than the expected carbon price under a U.S. cap-and-trade system (around $20-$30 per ton). In other words, the air-quality improvements alone could offset the cost of cutting carbon. A cap could be "worth it" for public health reasons, regardless of how one feels about global warming.