Too Much Screen Time Puts Children at Risk of 'Obesity and Cancer'
Spending too much time gawping at screens is making children more likely to be short-sighted, become overweight and get cancer, experts say.
A review of 80 studies on more than 200,000 people has ranked smartphones and tablets alongside sugary drinks as one of the biggest risks for childhood obesity.
Being overweight can lead to a dozen types of cancer, including breast, colon, kidney, liver, ovarian, pancreas and prostate.
As well increasing their risk of dying young, too much time on gadgets is damaging youngsters' eyes - the number of short-sighted children has doubled in 50 years.
Researchers say the findings are a 'significant concern' and call for more control on junk food adverts, which worsen the effects of children doing less exercise.
Research done by the World Cancer Research Fund examined the causes of weight gain in children around the world.
It found increasing amounts of time spent on smartphones, tablets and gaming is a big driver of children getting fatter - that and sugary drinks make up the top two.
'The report highlights the importance of acting early to help prevent cancer,' Sophia Lowes of Cancer Research UK told The Telegraph.
'Obese children are five times more likely to be obese as an adult, which is worrying because then they'll be at an increased risk of different types of cancer.
'That's why it's vital we see a 9pm watershed on junk food adverts on TV and similar protection for children viewing adverts on-demand and online.'
Experts say as well as leading to children doing less exercise, sitting inside looking at screens makes youngsters more likely to overeat on snacks.
They call this 'passive over-consumption' - meaning children snack on junk foods which they often see advertised on the same devices they're spending their time.
In addition to the obesity and cancer risks, spending too much time in front of screens also increase the number of children with myopia - short-sightedness.
The proportion of children worldwide with short-sightedness has more than doubled from 7.2 per cent to 16.4 per cent in the past 40 years.
This effect has been dubbed 'digital myopia', and King's College London researchers, in a separate study, found every hour a day spent on devices raised a child's risk of sight damage by three per cent.
Past research has suggested children spend, on average, eight hours a day using gadgets.
Professor Chris Hammond, from King's College, told The Telegraph: 'I think it is a significant concern.
'We do believe that young children staying indoors and spending hours on screens is bad for eyesight, not to mention obesity and fitness.
'I think our concept in myopia is clearly that close work is a risk factor, and outdoor activity is protective.'
Eye expert Dr Mohamed Dirani wrote in the British Journal of Opthamology: 'The age of smart device uptake is getting younger, with many two-year-olds spending up to two hours a day on devices.
'The use and misuse of smart devices, particularly in our paediatric populations, must be closely monitored to address the emerging phenomenon of digital myopia.'