It’s time to revisit a controversial subject…cellphones and our health. I last wrote on this topic in 2007, and disagreement over cellphone safety continues. In recent years a large number of studies from over a dozen countries have been published showing no evidence of a detectable link between cellphone use and brain cancers. This should be reassuring.
Nevertheless, there are hard-core believers, including scientists, who promote contrary views. Well-educated friends of mine continue to avoid putting their cellphones up against their ear. On the other hand, teenagers all over the world continue to hold their cellphones against their ears, in their pockets, and even under their pillows, 24/7. Should we be concerned?
Cellphones emit radio frequency energy, and the quantity to which a cellphone user is exposed depends on the technology of the phone, the distance between the phone and the user, the distance from cellphone towers, and how much the phone is used. Radiofrequency energy is a form of non-ionizing electromagnetic radiation, which can be absorbed by tissues closest to where the phone is held. While ionizing radiation is known to increase the risk of cancer (even the radiation therapy we use to fight cancer has the potential to cause other cancers), many studies have examined the potential effects of non-ionizing radiation, and have found no cancer connection to date.
Microwave ovens use this non-ionizing radiofrequency energy for heating. Likewise, the radiofrequency exposure from our cellphones causes heating, but not enough to measurably increase body temperature. One recent study showed that using a cellphone for 50 minutes caused the brain tissue on that side of the brain to metabolize more glucose than did tissue on the opposite side of the brain. Whether that is dangerous is inconclusive.
It is generally accepted that damage to DNA is necessary for cancer to develop. To date, radiofrequency energy has not been shown to damage DNA (unlike ionizing radiation), but researchers are certainly searching for such evidence. One Israeli study compared the saliva of 20 heavy cellphone users (more than 30 hours per month) with the saliva of 20 people who did not use a cellphone. The study found that exposure to cellphones causes oxidative stress, which harms human cells and DNA and contributes to a “carcinogenic effect.” These researchers advocate caution, but not stopping all cellphone use. This small study is by no means conclusive.
In 2011, the World Health Organization classified cellphones as possibly carcinogenic to humans. Note that power line exposure, talc-based body powder, and coffee are similarly classified.
Other current research is zeroing in on changes in brain activity, reaction time, and sleep patterns. To date, these effects are minor and have no apparent health significance. Other interesting studies investigate cellphone use near medical devices such as pacemakers, implantable defibrillators, and hearing aids. They do show possible interference, however the effect appears to be declining with newer technology. What has been conclusively proven is this: the risk of traffic accidents increases by three to four times when cellphones are used - whether handheld or hands-free!
Research continues to address gaps in knowledge, cancer risk, long-term risk, and risks to children in particular. Let’s all continue to exercise reasonable caution – and stay tuned.
Dr. Alan Frischer is former chief of staff and former chief of medicine at Downey Regional Medical Center. Write to him in care of this newspaper at 8301 E. Florence Ave., Suite 100, Downey, CA 90240.
Published: April 24, 2014 - Volume 13 - Issue 02