Love that blue light? You might want to back away, according to a sobering new study. An international team of researchers led by the Barcelona Institute for Global Health has found that exposure to blue light at night may increase your risk of developing breast or prostate cancer, reports Science Daily. The researchers analyzed medical and environmental data of more than 4,000 people in 11 Spanish regions. They used questionnaires to assess exposure to indoor artificial light and images from the International Space Station to gauge exposure to outdoor artificial light in Barcelona and Madrid. They found that exposure to high levels of outdoor blue light at night could boost a woman's risk of breast cancer 1.5-fold and increase a man's risk of prostate cancer two-fold.
One notable finding: Men exposed to high levels of indoor artificial light caused by sleeping in highly illuminated bedrooms had a 2.8-fold higher risk of developing prostate cancer than men who slept in total darkness. Should you be worried about blue light from your smartphone and tablet? Not yet, a lead study author tells CNN. Alejandro Sánchez de Miguel says they only looked only at blue light emitted by outdoor sources, not smartphones or tablets. Nevertheless, he cautions, "The same mechanism may be affecting the phones or the bulbs at home, because the physiology is the same." He says this is the first study to specifically analyze cities' blue light, which is known to lower the amount of melatonin in the brain and affect the body's circadian rhythm. (Read more cell phones stories.)