Dr Alejandro Sánchez de Miguel, from Exeter, said: “Humans have evolved to need light during the day and darkness at night. “As towns and cities replace older lighting, we’re all exposed to higher levels of “blue” lights, which can disrupt our biological clocks.”
“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.”
Blue light is a range of the visible light spectrum emitted by most white LEDs and many tablet, phone and TV screens.
It has one of the shortest, highest-energy wavelengths and previous research has indicated that exposure to blue-spectrum light decreases the production and secretion of the melatonin hormone.
Melatonin plays a key role in regulating the day-night cycles and has several other key functions – for example it is a powerful anti-oxidant and has also an anti-inflammatory function.
Dr Manolis Kogevinas, head of the Cancer Research programme at ISGlobal, The Barcelona Institute for Global Health, who coordinated of the study, said: “The World Health Organisation’s International Agency for Research on Cancer (IARC) has classified night shift work as probably carcinogenic to humans.
“There is evidence pointing to an association between exposure to artificial light at night, disruption of the circadian rhythm, and breast and prostate cancers.”
Earlier this month it was revealed Kent County Council is installing 118,000 LED lights on its streets, Leicestershire plans to have 68,000, Manchester 56,000 and Gloucestershire 55,000.
The study is published in Environmental Health Perspectives.