Women who live in neighborhoods with large amounts of nighttime illumination are more likely to get breast cancer than those who live in areas where nocturnal darkness prevails, according to an unusual study that overlaid satellite images of Earth onto cancer registries.And the energy bill signed into law in December mandates phasing out incandescent bulbs over the next dozen years. Sheet.
The finding adds credence to the hypothesis that exposure to too much light at night can raise the risk of breast cancer by interfering with the brain's production of a tumor-suppressing hormone. . . .
The mechanism of such a link, if real, remains mysterious, but many scientists suspect that melatonin is key. Secreted by the pineal gland in the brain, the hormone helps prevent tumor formation. The body produces melatonin primarily at night, and levels drop precipitously in the presence of light, especially light in the blue part of the spectrum produced in quantity by computer screens and fluorescent bulbs.
Abraham Haim, a University of Haifa chronobiologist involved in the study, said the findings raise questions about the recent push to switch to energy-efficient fluorescent bulbs, which suppress melatonin production more than conventional incandescent bulbs. "This may be a disaster in another 20 years," Haim said, "and you won't be able to reverse what we did by mistake." He called for more research before policies favoring fluorescent lights are implemented, and for more emphasis on using less light at night.
Tuesday, February 19, 2008
Strange science: nighttime light increases breast cancer rates