Night-time exposure to blue light associated with increased risk of colorectal cancer

https://www.eurekalert.org/pub_releases/2020-07/bifg-net072720.php


News Release 29-Jul-2020
Barcelona Institute for Global Health (ISGlobal)


Blue light has become an increasingly common component of urban outdoor lighting. But how does it impact our health? A team led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by the "la Caixa" Foundation, has conducted the first study of the association between night-time exposure to outdoor artificial light and colorectal cancer. The findings, published in Epidemiology, show that exposure to the blue light spectrum may increase the risk of this type of cancer.

Previous studies have found associations between night-time exposure to artificial light--especially blue light--and various adverse health effects, including sleep disorders, obesity and increased risk of various types of cancer, especially in night-shift workers. Blue light is a range of the visible light spectrum emitted by most white LEDs and many tablet and phone screens. An earlier study by ISGlobal found a link between exposure to blue light at night and increased risk of breast and prostate cancer.

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Results from both cities showed that participants with the highest exposures to blue light had a 60% higher risk of developing colorectal cancer than the less exposed population. No association was found with full-spectrum light.

"Night-time exposure to light, especially blue-spectrum light, can decrease the production and secretion of melatonin, depending on the intensity and wavelength of the light," explains Kogevinas.

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