7 Surprising Ways Cell Phones Affect Your Health

March 9, 2009— -- In recent years, public fears over the radiation emitted from cell phones have led to several theories about the health conditions this radiation might engender.

Almost invariably, the assertions that the use of cell phones may lead to a higher risk of brain cancer, that their use by pregnant women may result in badly behaved children -- even a video that suggested that the waves from two cell phones could be used to cook an egg -- have been discredited by scientific investigation.

"Current scientific evidence doesn't indicate any adverse health outcomes associated with exposure to radio frequency energy from cell phones," U.S. Food and Drug Administration spokeswoman Peper Long told ABCNews.com last May.

"Although there have been reports of negative health effects from low levels of radio frequency energy, these reports have not been replicated or confirmed."

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So those who suspect their phones are frying their brains can likely rest easy. However, research and anecdotes have suggested a number of other means by which cell phones may adversely affect health -- and possibly not in the way you might think.

What the researchers found was that 94.5 percent of the phones tested -- nearly 19 out of 20 -- were contaminated with some kind of bacteria. Worse, some of the bacteria that the researchers found were known "superbugs" -- bacteria that are resistant to one or more commonly used antibiotics.

Despite this, the researchers found that only about 10 percent of the health care workers studied cleaned their cell phones on a routine basis.

"Mobile phones are frequently-used devices with clean or dirty hands in daily practice, including in hospitals," Dr. Ahmet Dilek of the Ondokuz Mayis University team told ABCNews.com. "[W]e found that most of the medical professionals do not clean their own cell phones, and most of the [unclean] phones carried important hospital pathogens."

Dr. Charles Gerba, a microbiologist and germ expert at the University of Arizona in Tucson, has performed similar studies on cell phones. He said that his past research, too, has found that cell phones are a haven for a variety of microbes -- some of which are pretty nasty.

"We have found [the superbug] MRSA on several cell phones," he said. "So we certainly find a lot of stuff on them -- particularly the flip kind, since they have surfaces that do not dry out."

The solution to this problem may be decidedly low tech -- disinfectant spray and a paper towel.

"I think that they should wipe [their cell phones] down with a disinfectant wipe, or spray a towel with disinfectant and wipe the phones off," Gerba said. "They should be doing that at least once a day, if not maybe twice a day."

"The science tells [us] when [we're] on the phone while driving, it is a high-risk activity -- very, very risky," Janet Froetscher, president and CEO of the National Safety Council, told ABC News correspondent Lisa Stark in a "World News" report in January. "But most people don't understand that."

Still, 80 percent of drivers admit to having had a cell phone conversation while driving, according to a May 2008 Nationwide Insurance poll -- even though more than 40 percent of those surveyed said they'd been hit or almost hit by another driver who was talking on a cell phone.

Even hands-free phones appear to contribute to unsafe driving. A 2005 study by the Insurance Institute for Highway Safety found that drivers using cell phones -- even hands-free -- were four times as likely to have an accident involving an injury, according to Ann McCartt, senior vice president for research at the insurance institute.

"I think there is still a big misconception among drivers and policymakers, intuitively, that a hands-free phone would be safer," she said. "And there may be a margin of safety there, but it is still unsafe."

What they found was that when children were on the cell phones, their attention to traffic -- the number of times a participant looked right or left -- went down 20 percent. The risk of getting hit by a car, or the number of close calls, went up 43 percent.

"The influence of cell phones on child pedestrian safety is particularly concerning because cell phones, an oddity a decade ago, are quickly becoming ubiquitous among American schoolchildren," said the study's authors.

Some preliminary studies show that even adult pedestrians get distracted while carrying on cell phone conversations while walking. Still, adults are much more likely to avoid injury, as they are generally more adept at navigating the crosswalk than children are.

"If you use your cell phone a lot, it becomes part of you," Dr. William Barr, the chief of neuropsychology at the New York University School of Medicine, told ABCNews.com. "It's like wearing a tight sock all day. When you take it off, you still feel it there on your foot. If your cell phone is not there, you still feel like it is."

Our reliance on our cell phones may actually be "training" some of us to believe it is vibrating when it is not. In the case of cell phones, people are rewarded when they pick up their calls and read their incoming text messages, which causes them to pick up their cell phones more and more frequently.

"People are rewarded when they are able to detect low amplitude vibrations so they get better and better at responding," said Jon Kaas, a professor of psychiatry at Vanderbilt University. "It is very rewarding to get the message, so people are able to train their system to detect that signal."

As people repeat this behavior over and over again, connections between nerves in their brain become stronger and new ones are formed, which helps to make the behavior automatic.

And sometimes, as is the case with vibrating cell phones, the behavior becomes too automatic.

"People have gotten so good at detecting vibrations that they start responding to false positives -- they think something is there when it is not," Kaas said.

"They are really repetitive stress injuries -- pain, numbness, discomfort in the base of the thumbs from overuse," Margot Miller, a physical therapist and president of the Occupational Health Section of the Orthopedic Section of the American Physical Therapy Association, told ABCNews.com.

These sorts of injuries, known as repetitive strain injuries or a repetitive motion disorders, are sometimes minor. But they can also lead to serious medical problems.

"I've seen a significant increase in the number of people with pain in their tendon regions in their thumbs and their fingers," Dr. Richard Brown, an orthopedic hand surgeon at the Scripps Memorial Hospital in La Jolla, Calif., said.

"I have to send them to the therapist or start them on medicine or put them in splints or, sometimes even operate."

"Some people are extremely nickel-sensitive," Dr. Lionel Bercovitch, a professor of dermatology at Brown Medical School, told Kirk Fernandes of ABC News OnCall.

Nickel is a metal that's used in a wide variety of products, including jewelry, belt buckles and watch bands. It's the most common cause of contact dermatitis in the developed world.

The symptoms of a nickel reaction range from mere redness to an obvious rash, or even blisters.

"My guess is that [the reactions are] probably more common than we think, but it's just not widely recognized," he said.

In a study published in the Canadian Medical Association Journal in January 2008, Bercovitch tested 22 models of cell phones for the presence of nickel. He found that 10 devices contained the metal -- often around the menu buttons, near decorative logos, around the edge of the screen or on a part of the handset where paint was chipped.

"As more cases get reported, more people will begin to think about it," Bercovitch said.

According to statistics from the U.S. Centers for Disease Control and Prevention (http://www.cdc.gov/healthyyouth/noise/index.htm), about 12.5 percent of children and adolescents 6 and 19 years old and 17 percent of adults between 20 and 69 years of age have suffered permanent damage to their hearing from excessive exposure to noise. In total, this accounts for more than 30 million people.

Sounds louder than 85 decibels can damage hearing. Normal conversation is about 60 decibels, and stereo headphones out of our MP3-enabled devices often reach 100 decibels.

Fortunately, this noise-related side effect is easily remedied. Simply turning down the volume can limit chronic exposure to loud noises -- quite possibly ensuring that our future conversations on our cell phones continue to come in loud and clear.

Reports from Lisa Stark, Kirk Fernandes, Kamal Menghrajani and Carla Williams contributed to this report.

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