Cell Phone Use Frequently Asked Questions

Center for Environmental Oncology
University of Pittsburgh Cancer Institute
August 1, 2008

How can cell phones cause cancer, since they don't directly damage DNA or break chemical bonds?

Cancer is a complex disease that occurs when cells lose their ability to stay in order.  Scientists know that cancer results from many different types of damage to our bodies that take place over a long period in a multistep process.  The disease can begin with damage to the basic building blocks underlying all living cells--our DNA.  When DNA is damaged, cells can get signals to grow without controls, which can lead to more than 200 forms of cancer.  But sometimes the disease occurs without direct genetic damage to our DNA, as for instance when asbestos is inhaled deeply into the lung causing inflammation that triggers cancer several decades after exposure started. 

For many types of cancer direct DNA damage can start the cancer process by causing our healthy genes to lose their ability to repair the sorts of damage that happen everyday through sunlight and other normal parts of modern life.  Genes that usually suppress abnormal cell growth can get switched off, while those that boost dangerous growth can get turned on.

In addition to direct genetic damage, studies have shown that cancer genes can be affected by factors that have nothing to do with DNA.  There is growing evidence that chemicals and physical agents such as electromagnetic fields can also affect the chances that cancer will occur either by damaging the capacity of the immune system to fend off damage or through some other path that damages the proteins that usually  keep our bodies in balance.

The data on cell phone use and cancer is incomplete and inconsistent at this moment, but some studies do show that cell phone radiation has the capacity to disturb normal cells and the cell phone industries own studies show that the cell signal is absorbed deeply into the brains of children, and up to2 inches into an adult skull.  Some studies of populations that have used cell phones for longer periods of time have found some increased risk of serious brain tumors,while others have not.  More research is needed to determine if cell phones cause cancer and, if it does, exactly how this happens.  But, because brain tumors can take several decades to arise, the absence of conclusive evidence at this time should not be misconstrued as proof that there is no problem.

Why should I be worried about using my cell phone?

Manufacturers report that cell phones emit electromagnetic radiation that can penetrate the brain. It can take a decade or more for brain cancer and other serious diseases to develop. Ten years ago about one in four people used cell phones; today nearly nine out of every ten do. At this time, we can not say definitively whether cell phones are safe or not. However, a growing body of evidence, from countries where phones have been used for a long time, suggests that decade-long use of cell phones may increase the risk of developing serious health problems like cancer.

I have to carry my cell phone with me at all times, what should I do to limit my exposure?

If you must carry your cell phone on you, it is preferable that the keypad is positioned toward your body and the back is positioned toward the outside of your body. Depending on the thickness of the phone this may provide a minimal reduction of exposure.You can also put the phone on “off-line” mode which stops the electromagnetic field and turn it on when you need to use it. In addition, avoid keeping your phone near your body at night (like under a pillow or on a bedside table). Be especially cautious if you are pregnant or trying to become pregnant.

Is there anything I can do to help reduce the risk of electromagnetic fields when I’m talking on the phone?

Yes. Try to keep the phone away from your body. Whenever possible, use the speaker phone mode, or a hands-free kit equipped with an air tube inserted in last few inches nearest your ear piece. A wireless Bluetooth earpiece, using an infra-red signal, produces only 1/100th of the electromagnetic field of a normal cell phone.

How far from the body should I hold the phone?

The farther the phone is from the head, the weaker the signal that reaches the brain. If you hold it 2" away, the signal has 1/4 the strength. At 4" away, the signal is 1/16 as strong--this is because the strength of the signal drops off as the square of the distance.

Is text messaging a safer alternative to talking on the phone?

Yes. Texting will limit the duration of your exposure as well as increase the distance between your head and the phone. Both of these actions reduce the strength of electromagnetic radiation you receive. However, only choose text messaging when it is safe to do so. Never text message while driving.

Is it safe for my child to use a cell phone?

You should not allow children to use a cell phone except in emergencies. The developing organs of a fetus or a child are the most sensitive to any possible effects of exposure to electromagnetic fields. Also, because a child’s brain doubles in the first years of life, the electromagnetic field reaches much more deeply into a child’s brain than an adult’s.

Figure 1. Model estimate of the absorption of electromagnetic radiation from a cell phone based on age (Frequency GSM 900 Mhz) (On the right, color scale showing the Specific Absorption Rate in W/kg) [1]

Because of the brain’s smaller size and thinner skull the model predicts that significantly more electromagnetic radiation will be absorbed by the brain of a five year old compared with a fully developed adult sized brain.

If some of the research suggests that long term cell phone use may have health effects are countries urging caution?

In the U.S., the Federal Drug Administration (FDA) has recommended placing more distance between your body and your phone or using a headset to reduce your expose to electromagnetic radiation. [2]

In fact, the governments of other nations, including France, India, Canada, and Israel have all issued warnings about the dangers of electromagnetic fields emitted from cell phones.

Is there anything I can do to limit my exposure if I have to have the phone next to my ear?

You should switch sides regularly while communicating on your cell phone to spread out your exposure. Before putting your cell phone to the ear, wait until your correspondent has picked up. This limits the power of the electromagnetic field emitted near your ear and the duration of your exposure.

Do all phones emit the same amount of electromagnetic radiation?

No, not all phones are the same. You should choose a device with the lowest SAR possible (SAR = Specific Absorption Rate, which measures the strength of the magnetic field absorbed by the body) compatible with your type of usage (lower SAR phones emit fewer electromagnetic radiations but will not work as well in remote areas). SAR ratings of contemporary phones manufactured by different manufacturers are available by searching for “SAR ratings cell phones” on the internet.

Why isn’t there more definitive proof of whether cell phones cause harmful effects on our bodies?

Human epidemiological studies on cell phones conducted to date cannot be conclusive. Because increased use by large groups of people is a relatively new phenomenon, we are not yet able to evaluate their long term impact on health. Definitive cell phone studies are needed to clarify the magnitude of the risk and we are requesting that the cell phone companies provide scientists independent access to cell phone use records so that appropriate studies to evaluate cell phone use and health effects can be carried out.

1. Gandhi, O.P.G. Lazzi, and C.M. Furse, Electromagnetic Absorption in the Human Head and Neck for Cell Telephones at 835 and 1900 MHz. IEEE Transactions on Microwave Theory and Techniques, 1996. 44(10): p. 1884-1897.
2. http://www.fda.gov/cellphones/qa.html#3