Using tablet at night raises bowel cancer risk
TOO much artificial light at night raises the risk of bowel cancer by 60 per cent, a study has found.
Night-time exposure to the “blue” light emitted by most white LED lamps, tablets and phone screens increases the chances of developing the disease, as well as other health problems including sleep disorders and obesity, according to the findings.
Bowel cancer, also known as colorectal or colon cancer, affects more than 250,000 people in the UK and is the second most common cause of cancer death. While blue light is naturally found in sunlight, close exposure over a long period of time can suppress the body’s melatonin, a hormone which regulates the body clock.
About 2,000 adults who lived in Barcelona or Madrid were surveyed, of whom 660 had bowel cancer and the rest were randomly selected from the local population.
Images from the International Space Station were then used to determine the level of blue light at night in each area. People who lived in areas with the highest levels had a 60 per cent higher risk of developing colon cancer than those who were less exposed.
Study coordinator Dr Manolis Kogevinas, of the Barcelona Institute for Global Health, Spain, said: “There is growing concern about the effects of light on ecosystems and human health.
“Night-time exposure to light, especially blue-spectrum light, can decrease the production and secretion of melatonin, depending on the intensity and wavelength.
“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.”
Breast cancer and prostate cancer have both been linked to blue light exposure at night in earlier studies.
Night-shift work is classified as “probably carcinogenic” by the World Health Organization’s International Agency for Research on Cancer.
The findings were published in the journal Epidemiology.