A new study has warned of the dangers of overexposure to blue light, including light from phone screens late at night, which can raise the risk of colon cancer by as much as 60%.
Blue light, especially when emitted at night can also increase the risk of developing other health problems including obesity and sleep disorders, according to Barcelona Institute for Global Health researchers.
Previous research has linked blue light exposure at night with an increased risk of prostate and breast cancers. With this new finding, night-time workers are being warned of likely developing another form of cancer.
Colon cancer, also called colorectal or bowel cancer, is the second most common cause of cancer death. Over 250,000 people in the U.K. are afflicted with this type of cancer.
"Using the same methodology as the previous study, we decided to analyze the relationship between exposure to artificial light and colorectal cancer, the third most common type of cancer worldwide after lung and breast cancer," said Dr. Manolis Kogevinas, study coordinator of the Barcelona Institute for Global Health.
The research team surveyed approximately 2,000 adults in the cities of Madrid and Barcelona for the study, with more than 650 of them diagnosed with colon cancer. They determined the level of blue light at night-time in both cities using images from the International Space Station.
According to researchers, residents in the two Spanish cities living in areas with the highest exposure to blue light had a higher risk of developing colon cancer compared to cities that were less exposed. The team noted that blue light is emitted by mobile phones, tablets, and most white LED lamps.
This type of artificial light produces a lot of energy. However, close exposure for extended periods will cause the body to cease producing melatonin. This hormone helps the body regulate the sleep-wake cycle and is also a powerful antioxidant.
According to experts, blue light may disrupt the circadian rhythm of the body and results in an imbalance in hormone levels. Both prostate and breast cancers are hormone-related.
Researchers are continuously studying the effects of light on human health. Dr. Kogevinas said that research on the potential effects of light exposure is still in its infancy, so more work is needed to provide sound, evidence-based recommendations to prevent adverse outcomes.
The paper written by the research team at Barcelona Institute for Global Health has been published in the journal Epidemiology