Fact check: do mobile phones cause cancer?

The debate about the link between mobile phones and cancer has been raging for more than two decades – and shows no sign of slowing.

A recent study presented evidence that mobile phone radiation can cause cancer in rats, but previous research on humans has found that phone users appear to have no increased risk of developing the disease.

Amid widespread confusion over the possible health effects, The Week takes a deeper look at the research.

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What did the new study find?

A peer review of a landmark US government study, released in March, concluded that there was “clear evidence” that radiation emitted by mobile phones caused heart cancer in male rats.

The results “go against the notion that non-ionizing radiation is completely harmless”, study co-author Dr John Bucher told Vox.

Researchers at the National Toxicology Program, run by the US Department of Health, tested 3,000 rats and mice for two years - the largest investigation on non-ionising radio-frequency radiation and cancer in rodents ever undertaken in the US, according to Scientific American.

The review of the study also found “some evidence” that phone radiation caused cancer in the rats’ brains and adrenal glands.

However, experts caution that “the jury is still out as to whether wireless technology is similarly risky to people”, the magazine adds.

Previous human studies have found no link between mobile phone use and most types of cancer.

But a “lack of definitive proof that a technology is harmful does not mean the technology is safe”, says Mark Hertsgaard, environment correspondent for The Nation, and investigative historian Mark Dowie.

In a recent article for The Guardian, the pair accuse the wireless industry of successfully “selling this logical fallacy” to the public as part of an orchestrated PR campaign.

“Over the past 30 years, billions of people around the world have been subjected to a public-health experiment: use a mobile phone today, find out later if it causes genetic damage or cancer,” they say.

“Meanwhile, the industry has obstructed a full understanding of the science, and news organisations have failed to inform the public about what scientists really think.”

What do major cancer charities say?

The scientific evidence to date shows it is “unlikely” that mobile phones could increase the risk of developing brain tumours or any other type of cancer, according to Cancer Research UK.

“But we do not know enough to completely rule out a risk,” the organisation warns.

The American Cancer Society has come to similar conclusion. It agrees that most of the research published so far has not found a link between mobile phone use and the development of tumours, but notes that the studies had “some important limitations that make them unlikely to end the controversy”.

What about health organisations?

Mobile phones are currently listed as “possibly carcinogenic” by the World Health Organization’s International Agency for Research on Cancer (IARC). This puts mobiles in the same category as coffee and means that a link could not be ruled out but could not be proved either.

The NHS, meanwhile, says most current research suggests it’s unlikely that radio waves from mobile phones or base stations increase the risk of any health problems.

However, “this evidence is based on use of mobile phones over the last 20 years, and there’s still some uncertainty about possible health effects from using a phone for longer than this”, says the NHS website.

Some of the biggest studies and their results

The Interphone study (2010) In this international case-controlled study, sponsored by IARC, researchers compared cancer patients with healthy control groups to see if their mobile usage in the past had differed. The decade-long study, which covered more than a dozen countries, found that overall, mobile phone users showed no increased risk of developing brain cancer.

“If you look at the overall evidence, this study did not confirm or dismiss the possible association between cell phones and brain tumours,” said Interphone researcher Siegal Sadetzki, a public health physician at Tel Aviv University’s Sackler Faculty of Medicine. “That’s the bottom line.”

The Danish cohort study (2011) Led by the Institute of Cancer Epidemiology in Denmark, this cohort study tracked more than 350,000 people with mobile phones over an 18-year period. Researchers compared the occurrence of brain and central nervous system tumours in mobile phone subscribers and non-subscribers and found no increased risk among mobile phone users, even those who had used them for the longest period.

The Million Women study (2013) This prospective study by the NHS and Cancer Research UK is the largest of its kind to date, involving 800,000 women in the UK. The research examined the risk of developing brain tumours over a seven-year period in relation to self-reported cell phone use at the start of the study. Researchers found no link between mobile phone use and most types of brain tumour or 18 other types of cancer. They did, however, see a possible link between long-term use and a rare type of brain tumour, known as acoustic neuroma. But an update to the study, which included additional data, showed that this link was no longer seen.

What is the consensus?

The evidence published so far shows that mobiles are unlikely to cause cancer in humans. However, research in this field is still ongoing and experts are unable to rule out the dangers of long-term mobile phone use.