Tuesday, February 3, 2009

Health Benefits of Dark Sky Cities

Some people have an intense desire to live in an area with a very dark sky at night. Many of my friends and neighbors feel this way, so they've chosen places like Sedona, Flagstaff or Tucson, Arizona in which to live. Now, it seems as if this need to live in a "dark sky city" may have a basis in health.

In Israel and Connecticut, a new study has been published which originated at the University of Haifa. This study discovered that worldwide, countries with the highest levels of artificial light at night also have the highest rates of prostate cancer. The new study concludes that countries in which nighttime artificial lighting is used more intensively tend to have a higher risk of prostate cancer in men. This joins a previous finding that was published in Chronobiology International in 2008, in which exposure to artificial lighting at night increases the incidence of breast cancer in women.

At the very first stage of the study, it already became clear that there is a marked link between the incidence of prostate cancer and levels of nighttime artificial illumination and electricity consumption. The results demonstrated that the incidence of prostate cancer in those countries with low exposure was 66.77 prostate cancer patients to 100,000 inhabitants. An increase of 30% was found in those countries with medium exposure: 87.11 patients per 100,000 inhabitants. The countries with the highest level of exposure to artificial light at night demonstrated a jump of 80%: 157 patients per 100,000 inhabitants.

According to these researchers (Prof. A. Haim, Prof. B. A. Portnov, and Itai Kloog of the University of Haifa, together with Prof. R. Stevens of the University of Connecticut), there are a number of theories that could explain the increased incidence of prostate cancer due to exposure to lighting at night, such as suppression of melatonin production, suppression of the immune system, and an effect on the body's biological clock because of confusion between night and day. Whatever the cause, there is a definite link between the two. "This does not mean that we have to go back to the Middle Ages and turn the lights out on the country. What it means is that this link should be taken into account in planning the country's energy policies," the researchers pointed out.

An increased level of nighttime artificial lighting is considered by many, including the World Health Organization, as a source of environmental pollution. And I can tell you from personal experience there is nothing better than taking a walk outdoors on a beautiful evening lit only by the moon and the stars.


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