Health professionals often warn that late night cell phone usage can keep you awake, but a new study found a more alarming reason to give up browsing the internet in bed: prostate cancer.
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. There’s been emerging evidence that this could increase people’s cancer risk — and now, a study published in the journal Environmental Health Perspectivesreveals that blue light exposure could double a man’s risk of prostate cancer or increase a woman’s chances of developing breast cancer by 1.5 times.
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 isn’t all bad news: The team also found that using dark window shades to block outside light may decrease your risk.
While the consequences of staring at your screen are still a little murky, mounting evidence suggests it’s probably best not to peruse Instagram for hours before bed (your self confidence will probably benefit, too.)