Two US government agencies provide conflicting interpretations of a safety study on mobile phone radiation: one says it causes cancer in rats. The other says there is no need to worry.
No new research was released on Thursday. Instead, the National Toxicology Program expressed its concerns about a link to heart and brain cancer from a study published last winter on male rats.
The Food and Drug Administration, which monitors mobile phone security, did not agree with the improved warning. "These findings should not be applied to the use of cell phones in humans," said Dr. Jeffrey Shuren, Chief of Radiological Health of the FDA.
Most importantly, what happens in humans is not in rats, said Dr. Otis Brawley, chief physician of the American Cancer Society.
"The incidence of brain tumors in humans has been flat for 40 years," said Brawley. "This is the absolutely most important scientific fact."
In a $ 30 million study, scientists put rats and mice in special chambers and bombarded them with radio frequency waves emitted by older 2G and 3G phones, nine hours a day for up to two years, the largest Part of their natural life.
The levels that rodents experienced were much higher than people are normally exposed to.
Last February, the National Toxicology Program stated that there was a slight increase in abnormal heart tumors in male rats, but not in mice or female rats. The agency concluded that there was "some evidence" of a connection. The February report also cited "dubious evidence" of brain tumors in male rats.
On Thursday, the agency updated its description of these results. The increase in the heart tumor marked "clear signs" of cancer in male rats. There is "some evidence" on brain cancer.
The change came after the agency asked external experts to analyze the results.
"We believe the link between radiofrequency radiation and tumors in male rats is real, and the external experts agreed," said John Bucher, chief scientist at the toxicology agency.
While his agency said that the risks to rats do not directly affect humans, the study raises safety issues.
The FDA immediately disagreed and issued a press release reassuring Americans that "decades of research and hundreds of studies" have convinced the health department that the current safety limits for mobile phone radiation protect the health of the population.
In addition, the FDA pointed out confounding results from the rodent study – for example, that the irradiated rats lived longer than control rats exposed to no radiation. The toxicology agency said the radio frequency energy had helped older rat kidneys.
There's a reason why two different government agencies collide – they ask different questions, said George Washington University's professor of health care, George Gray.
Gray, a former science chief of the Environmental Protection Agency, said the toxicology program investigated how cell phone radiation affected the animals. By examining what it means for humans, "the FDA is bringing in more information and data than just these new tests on rats and mice," he said in an email.
"I'll call you from my cell phone," Brawley told The Cancer Society.
He points to a known risk of mobile phones: car accidents when distracted from motorists.
When it comes to cancer, they could use headphones or speakers, he said.
Those who study the risk do not hang up.
"My family and I will not change our mobile phone habits because of this news," said George Washington's co-author of the book. "Risk: A Practical Guide to Deciding What's Really Safe and What's Really Dangerous in the World Around You."
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