Scientists with the National Toxicology
Program say there is some evidence that the radiation from cellphones can
increase the chance of having a rare type of nerve tumor, at least in male
rats.
What this means for people is still up for
debate.
As cellphone use climbs, questions about the
safety of these common devices have lingered. About 80% of Americans over the
age of 13 have a smartphone, and adults spend an average of nearly 3 hours a
day using one, according to a 2017 report from comScore, a data review company.
The tumors that showed up in the rats are
called schwannomas. They grew in the hearts of male rats, but not female rats,
perhaps because the males’ larger bodies absorbed more radiation than the
females, said lead researcher John Bucher, PhD. He is a senior scientist with
the National Toxicology Program.
Even though the tumors were in the rats’
hearts, the scientists said the finding was intriguing because previous studies
have noted a higher chance of having schwannomas in the inner ears of heavy
cellphone users.
In humans, schwannomas are incredibly rare
and usually benign.
They were rare in the rats, too. Only 6% of
the animals in the most highly exposed group got them.
The studies also found other biological
effects. Pups born to exposed rats weighed less than those born to unexposed
animals, for example; and they saw evidence of DNA damage in some tissues in
some animals, though Bucher said he and his team didn’t fully understand the
significance of those results.
In a surprise finding, radiation exposure
appeared to have some positive effects. Male rats that were exposed lived
longer than those that weren't. Researchers think that may be because the
radiation prevented a kidney disease that’s common in these kinds of rats.
Testing
Cellphone Radiation
The
findings come from a 10-year, $25 million investigation by the National
Toxicology Program.
Researchers used a format common in
toxicology studies, where they expose living things to more and more amounts of
an agent to try to find out two things:
o Whether it has any biological effects
o If it does, at what dose it creates those effects
It’s well-known that ionizing radiation --
the kind produced by X-rays and atomic bombs -- can cause harm.
But scientists haven’t understood whether
much weaker non-ionizing radiation -- the kind given off by cellphones and
microwaves -- could cause any damage.
Even the largest and best studies in humans
have had important limits that made it difficult to know for sure.
For the study, more than 3,000 male and
female rats and mice were housed in specially designed chambers where they
could be blasted with the same kinds of radiation that are emitted by mobile
phones.
The animals were exposed to the radiation
before birth and for as long as 2 years afterward. A 2-year-old rat is about
the same biological age as a 70-year-old human.
Bucher called the studies “some of the most
comprehensive and technically challenging” that the agency has ever tried.
The researchers tested the same kinds of
radiofrequency waves used in 2G and 3G wireless networks. In 4G networks, these
are the same kinds of waves used to make voice calls and send texts.
The doses they tested were higher than the
amount people are exposed to during a typical phone call.
Researchers said they tested these extreme
doses to try to find out if the radiation could cause any biological effects.
They chose the highest doses of radiation
they could expose the animals to without dangerously increasing their body
temperatures.
Study
Takeaways
In the end, Bucher said that they did see
some biological effects from the radiation, but they still don’t really
understand the importance of everything they found.
The studies will be reviewed by scientific
experts in March.
Federal agencies like the FDA will then meet
to talk about the studies and what they might mean for people.
Bucher told reporters he hasn’t changed his
cellphone habits based on the study findings, nor has he tried to change his
children’s cellphone habits.
“I think everybody would classify
radiofrequency radiation as a weak carcinogen, if in fact, it is a carcinogen,”
he said.
The FDA also weighed in, saying the findings
gave it further confidence that cellphones were safe to use.
“Even with frequent daily use by the vast
majority of adults, we have not seen an increase in events like brain tumors.
Based on this current information, we believe the current safety limits for
cellphones are acceptable for protecting the public health,” said Jeffrey
Shuren, MD, JD, director of the FDA’s Center for Devices and Radiological
Health.
Still, other experts say these new findings,
taken together with previous research, point to a need for caution.
“There have been a number of studies that
have consistently shown damage to DNA from cellphone radiation,” says Devra
Davis, PhD. “Animal testing is done to predict effects in humans.”
Davis is a toxicologist who once reviewed
studies for the National Toxicology Program. She now runs the nonprofit
Environmental Health Trust in Teton County, WY, which works to educate people
about the risks of using cellphones.
She says the fact that the radiation from
cellphones can change DNA means that they should be handled with care.
“Distance is your friend with cellphones.
Even a short distance away gives you substantially less exposure,” she says.
Using the phone with a headset or on speaker is safer, she says.
Davis tells people if they’re going to carry
their cellphone next to their body, put it in airplane mode, which drops the
radiation.
Parents need to be especially cautious
letting kids play with their phone. Kids’ growing tissues are more vulnerable
to damage.
“We have to stop thinking of these things as
toys and playthings for kids,” she says. “These are bad ideas.”
Lastly, she says the most dangerous time to
use a phone is when the signal is weak. Phones are smart, so they’ll boost
their energy output to try to connect to a base tower.
“Only use it for a true emergency when the
signal is weak,” she says.
Source: Web
MD
