In February 2018 researchers from the USA issued a warning to women with a family history of breast cancer to avoid using their smartphones, tablets and laptops at night. They stated recent research had shown that short-wavelength visible light reduced the secretion of melatonin in the body and caused circadian rhythm disruption. This finding had led the researchers to investigate the health effects of exposure to short wavelength visible light in the blue region emitted from digital screens. Results showed that when people used their smartphones at night both the blue light and radiofrequency electromagnetic fields generated by the mobile phone was linked to disruption of the circadian rhythm. They concluded that if women with a family history of breast cancer use their smartphones, tablets or laptops at night, there is a disruption in their circadian rhythms which can increase the risk of breast cancer. Using sunglasses with amber lenses, or smartphone applications which decreases the users’ exposure to blue light before sleep can, at least to some extent, decrease the risk of circadian rhythm disruption and therefore breast cancer.
Mortazavi SAR, Mortazavi SMJ. Women with hereditary breast cancer predispositions should avoid using their smartphones, tablets, and laptops at night. Iran J Basic Med Sci. 2018 Feb;21(2):112-115