Dec. 6, 2010 -- Exposure to cell phones before birth and afterward may increase a child’s risk for developing certain behavioral problems, including hyperactivity, inattention, and problems getting along with peers, a study suggests.
The study is published online in the Journal of Epidemiology and Community Health.
The new research does have limitations; the study researchers point out that there aren’t enough data to say how, or even if, cell phone exposure may cause any behavioral problems in children.
“There are theories, but we do not know,” says study researcher Leeka Kheifets, PhD, a professor of epidemiology in the UCLA School of Public Health. “Exposure to the fetus is likely to be very low, so it’s unclear how it can influence fetal development.”
But taking some simple precautions to reduce exposure during pregnancy and among children seems prudent. “Be aware of your exposure and while the science develops, use precaution,” she tells WebMD. “It is very easy to reduce exposure by keeping your phone away from body and using a hands-free device, so why not do it?”
Cell Phone Exposure and Behavior
The researchers analyzed data on cell phone use from 28,745 7-year-olds and their moms who were part of the Danish National Birth Cohort study. The mothers provided information on their lifestyle including cell phone use during and after pregnancy. They were interviewed again about their kids’ cell phone habits and behavioral issues when their children turned 7.
They found that 35.2% of 7-year olds used a cell phone. Less than 1% of children used their cell phone for longer than one hour a week. Based on the reports by their mothers, the majority of children (93%) had no behavioral issues, 3.3% had borderline behavioral problems, and 3.1% showed signs of behavioral problems including emotional symptoms, conduct problems, hyperactivity/inattention, and relationship problems.
Close to 18% of children were exposed to cell phones during pregnancy and after birth, and this was the group with greatest risk for behavioral problems, the study suggests.
The new findings mirror those of an earlier, smaller study of about 13,000 children from the same Danish birth cohort.
Going forward, Kheifets plans to look at the children when they turn 11 and see if the findings still hold. Children will be able to answer questions regarding their cell phone use for themselves by the time they are 11.
Reducing Cell Phone Exposure
The time to act is now, says Devra Davis, PhD, MPH, the founder of Environmental Health Trust, a group that educates the public about environmental health risks and pushes for policy changes needed to reduce these risks. She is also the author of Disconnect: The Truth about Cell Phone Radiation, What the Industry Has Done to Hide It, and How to Protect Your Family.
“Pregnant women should be careful about exposure for lots of reasons, not this study. Warnings actually appear on phones that say pregnant woman should avoid exposure to their abdomen,” she says.
“Do not keep it on your abdomen, use it with a headset or speaker phone,” she says.
Davis practices what she preaches; she spoke to WebMD using a headset with her cell phone. “It is better be safe than sorry,” she says. “We do not have a lot of data, and if we are smart we would not insist on waiting to get lots of data before taking these simple precautions.”
It’s not just pregnant women who need to heed this advice. Several studies have shown that men who keep their cell phones in their pocket may risk damaging their sperm, she says.
John Walls, vice president of public affairs at CTIA-The Wireless Association, a trade group representing the wireless industry, tells WebMD that his group “stands behind the research review by independent and renowned public health agencies around the world which states that there are no known adverse health effects associated with using wireless devices.”
Jeff Stier, a senior fellow at the National Center for Public Policy Research, a conservative think tank, says that the new study is full of holes. “For starters, self-reporting of cell phone use makes it impossible to assign any meaning to the exposure,” he says.
“Different phones give off different exposures, and even those who were reported to be not exposed, probably had significant environmental exposure, rendering the study only slightly more than amusing,” he tells WebMD in an email.