Modern street lamps and mobile phones are triggering thousands of cancer cases, according to new research.
A study from the University of Exeter found that men who live in large cities are twice as likely to develop prostate cancer, while women are one and a half times more prone to breast cancer.
Scientists blame the worrying trend of the & # 39; blue light & # 39; emitted by the LEDs. This reduces the levels of melatonin that controls the body's clock.
Both forms of the disease have been linked to the lack of the hormone that occurs during sleep.
The alarming findings also raise concerns about the blue light emitted by smartphones. and tablets, reports Devon Live.
In the United Kingdom, hundreds of thousands of streetlights have been replaced by LEDs that are cheaper to use and have fewer emissions.
Dr. Alejandro Sánchez de Miguel, of the University of Exeter, said: "Humans have evolved to need light during the day and darkness at night.
" As towns and cities replace lighting Older, we are all exposed to higher levels of "blue" lights, which can disrupt our biological clocks. "
He said the same applies to outdoor commercial lighting, such as advertising.
"It is imperative We know for sure if this increases our risk of cancer.
"Scientists have long suspected that this might be the case – now our groundbreaking findings indicate a strong link.
" We must also investigate whether night exposure to blue light emitted by smartphones and tablets increases our risk of cancer. "
His team compared medical and epidemiological data of more than 4,000 men and women between 20 and 85 years old in 11 areas of Spain, mainly around Madrid and Barcelona.
The analysis led by the Institute of Global Health of Barcelona (ISGlobal) found that the more blue the light emission was to urban dwellers, the higher the risk of cancer compared to those in suburban or rural regions.
He also showed those who they lived in houses with darker rooms, using blinds, for example, they had less risk.
The oldest lighting schemes emit a Glow within the spectrum & # 39; orange & # 39 ;, but the new modern lighting creates a brilliant emission & # 39; blue & # 39 ;. 19659003] Indoor exposure to artificial light was determined through personal questionnaires, with outdoor levels evaluated based on nighttime images taken by astronauts on board the International Space Station.
It was the first time this had
Dr de Miguel, who has researched light pollution for more than 20 years, said: "Now we must improve our research methods to ensure this is solid so that we can advise on the best way to protect human health.
"Currently, the images taken by astronauts on the International Space Station is our only way to determine the propagation of white LEDs emitting blue light in our cities."  Melatonin is produced by a gland in the brain, mainly between 9 pm and 8 a.
Lower levels can lead to an increase in estrogen levels, a suspicious trigger of breast cancer.
] It can also lead to an increase in genetic mutations, reduced DNA repair and a weakened immune system, which may increase the risk of prostate cancer.
study published in Environmental Health Perspectiv Little is known about how environmental factors affect breast and prostate cancer.
It is believed that LED lights interrupt the body's 24-hour cycle known as circadian rhythm, in turn affecting hormones.
related to the hormone.
Previous research has shown an increased risk between prostate cancer and night shift.
It is also known that artificial light, particularly in the blue spectrum, can decrease the body's production and secretion of the hormone melatonin.
Melatonin plays a key role in the regulation of day-night cycles and has several other key functions.
It is a powerful antioxidant and an anti-inflammatory function. But its role in breast and prostate cancer is still not understood.
Dr. Manolis Kogevinas, head of the Cancer Research program at ISGlobal, The Institute of Global Health Barcelona, which coordinated the study, said: "The International Agency for Research on Cancer (IARC) of the World Health Organization has classified night work as probably carcinogenic to humans.
" There is evidence that It points to an association with exposure to nocturnal artificial light, altered circadian rhythm and breast and prostate cancer.
"This study sought to determine if night exposure to light in cities can affect the development of these two types of cancer."
Co-author Professor Martin Aube, physicist at CEGEP (General and Professional College ), Quebec, said: "We know that depends on its intensity and wavelength, artificial light, particularly in the blue sp. Ectrum, can decrease the production and secretion of melatonin."
The first author, Dr. Ariadna Garcia, of ISGlobal, was added: "Given the ubiquity of artificial light at night, determining whether or not to increase the risk of cancer is a public health problem." 19659003] point, more studies should include more individual data using, for example, light sensors that allow to measure the interior light levels.
"It would also be important to do this type of research in young people who widely use the emission of blue light displays."
In the United Kingdom, prostate cancer is now the third deadliest form of the disease, killing to almost 12,000 men a year.
Breast cancer is next, claiming around 11,500 lives, annually.
The councils claim The LED lights reduce the use of energy by up to 40 percent.
Earlier this month it was revealed that the Kent County Council is installing 118,000 on its streets, Leicestershire plans to have 68,000, Manchester 56,000 and Gloucestershire 55,000.
Th There are five times fewer cases of breast cancer in developing countries, where electric light is less widespread than in industrialized nations.
The claims that shift work – carried out by 2 million women in Britain – could cause breast cancer 1987, although subsequent studies have not been able to establish a definitive link.