Everyday devices like cell phones, computer screens, and even street lamps emit blue light, which research shows disrupts our circadian rhythms and confuses the body about when it’s time for sleep. Apart from that, a study led by the Barcelona Institute for Global Health (ISGlobal) and involving the University of Exeter found that participants living in large cities with heavy exposure to blue lights at night had double the risk of prostate cancer and 1.5 times higher risk of breast cancer. This was compared to populations with less exposure to blue light.
Older lighting schemes emit a glow within the “orange” spectrum, but new modern lighting creates a bright “blue” light emission. The researchers found the bluer the light emission that people in large cities were exposed to, the higher the risk of cancer. The study also found that people who lived in homes with darker rooms, by using window shutters for example, had lower risk than those who did not.
The study, published in Environmental Health Perspectives includes medical and epidemiological data of more than 4,000 people between 20 and 85 years of age in 11 Spanish regions. It particularly examined Madrid and Barcelona. Indoor exposure to artificial light was determined through personal questionnaires. In the first study of its kind, outdoor levels of artificial light were evaluated based on night-time images taken by astronauts aboard the International Space Station.
To determine whether that evening glow could be dangerous, European researchers led by the Barcelona Institute for Global Health compiled data from more than 4,000 people. Participants included those with and without breast and prostate cancers between the ages of 20 and 85. The researchers used questionnaires to asses bedroom environments — like whether people slept in dark or dimly-lit rooms — and used photos from space to capture the levels of blue light found outdoors.
Their findings? Brighter bedrooms and areas with heavy outdoor lighting were associated with a higher risk of prostate cancer.
As towns and cities replace older lighting, we’re all exposed to higher levels of ‘blue’ lights, which can disrupt our biological clocks,” study co-author Alejandro Sánchez de Miguel, of the University of Exeter, said in a statement. “It’s imperative that we know for sure whether this increases our risk of cancer. Scientists have long suspected this may be the case — now our innovative findings indicate a strong link.”
Of course, this study doesn’t show causation — only that there’s a link between blue light and prostate cancer. Still, de Miguel called for further studies to determine whether our smartphone addiction could be deadly.
“We must also investigate whether night-time exposure to the blue light emitted by smartphones and tablets increases our risk of cancer,” he said.
The study was conducted within the framework of the MCC-Spain project cofunded by the ‘Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública’ (CIBERESP).
Ariadna García, ISGlobal researcher and first author of the study, says: “Given the ubiquity of artificial light at night, determining whether or not it increases the risk of cancer is a public health issue.
“At this point, further studies should include more individual data using for instance light sensors that allow measuring indoor light levels. It would also be important to do this kind of research in young people that extensively use blue light emitting screens.”
Source – University of Exeter, Men’s Health, Environment Health Perspectives.