AMA warns against light exposure at night
By JUDY SIEGEL-ITZKOVICH
University of Haifa researcher links over-exposure to cancer; AMA encourages further research into the matter.
The American Medical Association has issued an official statement warning
against the health hazards posed by exposure to artificial light for hours at
work or during sleep.
Prof. Abraham Haim of the University of Haifa’s
Israeli Center for Interdisciplinary Research on Chronobiology has conducted
research on the subject.
“The fact that the AMA has taken this matter
seriously and come to the conclusion that exposure to light at night is indeed a
health hazard is a form of recognition for the various studies that experts such
as Prof. Haim have been conducting over recent years,” the university stated on
Monday. The AMA’s policy announcement supports Haim’s research conclusions, it
The AMA, the largest association of medical physicians in the US,
recently announced its new policy recognizing adverse health effects of exposure
to excessive light at night, including disrupting sleep, exacerbating sleep
disorders and causing unsafe driving conditions.
The AMA encouraged
further research into the matter.
The policy also supports the need for
developing lighting technologies that minimize circadian (biological clock)
disruption and encourages further research on the risks and benefits of
occupational and environmental exposure to light at night.
studies, published in peer-reviewed medical journals, include research that found
that men who are exposed to artificial light at night have a higher risk of
developing prostate cancer.
Haim published this finding in Chronobiology
Although the cause has not been proven conclusively, the
study’s researchers suggested that repression of the production of melatonin
hormone in the brain and weakening of the immune system because of light
disruption at night of the biological clock – causing confusion between day and
night – could be the explanation.
“The findings do not mean that we have
to return to the Middle Ages and turn off all the lights at night,” the
researchers said, “but night illumination should be taken into account in the
planning of a country’s energy policy.”
The World Health Organization has
already called artificial illumination at night a “source of
In another study, Haim confirmed suspicions that exposure to
artificial light at night, including at the workplace, is a risk factor for
breast cancer. The retrospective study was carried out on 1,679 Jewish and Arab
Israeli women and the level of light to which they were exposed in their
bedrooms from street lamps outside the window, another room or night lights in
Even the light of a TV set was examined as a factor. Almost
half contracted breast cancer.