When we switch on the mobile phone, the signal is first carried to a tower, then to the intermediate station that recognises the caller and sends it to another tower that is close to the recipient. And finally, the signal reaches the antenna of the mobile phone that captures it and changes or modulates it into an audible sound. With all the hype around mobile phone towers and radiation, the question is – whether it can cause cancer? We spoke to Dr. Rakesh Jalali, Professor and Senior Oncologist at the Tata Memorial Hospital, Mumbai. He is a Radiology Oncologist, also has a Neuro-Oncology fellowship from Royal Marsden Hospital, London. With over 200 peer-reviewed papers and book chapters, he has also received Academic Award for Excellence for Best Global Original Research in Quality of Life for Patients at the Society of Neuro-Oncology in 2007.
According to Dr. Jalali, the concern arises because essentially we are using electromagnetic radiation. Even though it belongs to the lowest end of the spectrum in terms of frequency, it is still slightly more than the radio frequency waves used by radio. However, he is quick to point out that they are essentially non-ionising, which means they cannot cause direct damage to DNA. Direct DNA damage generally occurs because of ionising radiation. “Though the effect of non ionizing waves is very small, for 50 years people have been trying to see in laboratory using animal module, whether there is any damage to DNA. Initially results hardly showed any damage because there was no direct DNA link, but now people are exploring the possibilities of some indirect damage. So they have seen, for example, that it can affect the environment of the cell, it can affect the cell membrane, it can also sometimes affect the nucleus indirectly, it can release what are called free radicals which can predispose people to cancerogenic effect. Even WHO terms it 'potentially carcenogenic' that implies a probable link and it requires further research.”
Dr. Rakesh Jalali, Professor of Radiation Oncology, Tata Memorial Hospital
Though the effects of radiations are making headlines now, several studies have been conducted over the past 20 years to know the effects of radiations on humans. However, majority of the studies conducted till date haven’t been able to establish a direct link between the causation of brain tumor or cancer in general with the usage of mobile phone. Dr. Jalali points out one such important study and the possible reasons why such studies in the past have failed. Interphone is a study commissioned by WHO’s branch called International Agency for Research in Cancer IARC. The Interphone study was performed in 13 countries in the world and primarily in the Nordic countries (relatively non-migrating population and they were amongst the first one to use mobile phones). He says, “Talking about the overall result of the study, there was no direct link established between cancer and radiations. But if you look at it critically, there’s some interesting data like the maximum time that a person spends on phone was about 100 – 110 hours in the entire life which means around 20 hours per month and here sometimes people speak for 20 hours in probably few days. The study started roughly in 2000 when cell phone usage was not that high as it is the case now. And interestingly and of slight concern was that there was a small group of patients in whom there was a statistical significant increase in brain tumor and this group belonged to people who reported excessive usage of cell phones. This number was very small as compared to the overall sample size on whom the study was conducted.” So, probably, if today such a study is conducted, the results could be different.
While there is no direct link to prove the cause of cancer or even tumour, radiation can have other health effects. Specific absorption Rate or SAR, as it is more commonly known, is the more worrying factor with evident health implications. SAR is associated with your mobile devices. When mobile phones use microwave frequency waves, they do deposit some amount of energy and this energy is of two types – thermal energy and non-thermal. SAR is measured as watts per kg body weight. Higher the SAR, more is the possibility of deposition of that energy. Many international agencies, including the American Cancer Society, say that the power of the mobile phone energy deposition in the human tissue should not be more than 1.6 watts per kg. So, it is important that you check the SAR of your handset before purchasing it. In any case, there will be some deposition of energy, but the heat temperature is extremely mild at .01 degree centigrade (you don’t feel the heat). Nevertheless, it also depends on the length and duration of the calls you make. Recently, DoT reduced the SAR value from 2 watts per kg to 1.6 watts per kg, it has also made it mandatory for the mobile phone manufacturers to mention the SAR value of every handset on their website. This also applies to the mobile devices being imported to the country.
Mobile phone and SAR (Image Credit: Interphone, IARC)
Even with the reduced values, SAR can be potentially harmful to your health. However, this depends on your phone usage and so is in your control. Dr. Jalali, while explaining the impact of SAR, points out that all electromagnetic radiations are governed by the inverse square law, which means longer the distance of the source to the tissue, the less is the effect of the energy deposition. Speaking about the ill effects of such energy deposition he says, “People have reported headaches which could be because there is a temporary thermal deposition on the hearing nerve due to the hearing apparatus of the phone. Depending on person to person some have complained of hearing loss, they have complained of tinnitus – ringing sensation in the ear, people have also complained of fatigue because of excessive use of cell phone.” He advises people to use mobile phones sparingly, as he thinks there is an over dependency on phones that not many people realize. He adds, “It’s easy to blame the cell phone towers, cell phone companies, but it’s ourselves we have to blame. There is mobile phone etiquettes and there is cell phone culture, which I have particularly noticed is very low in our country.”
Dos and don’ts
- Use the phone judiciously
- Hold it away from your body. Use speakerphones or Bluetooth headsets while talking on the phone
- When you use the phone, try to alternate the side of the face you are using
- Try to avoid using mobile phones whenever there is a weak signal, as that’s when it uses more power and so the energy deposition is much more
- Do not press the phone against your head to hear more clearly
- Resort to texting rather than making phone calls whenever possible
- Do not keep the mobile phone next to you or under your head while sleeping
- Check the SAR value of the handset before buying it
- Use the landline instead of mobile phone whenever possible
- Avoid using the phone when your hair is wet and hold it away if you are wearing a metal spectacle frame, as water and metal are good conductors of radio waves
- Children should limit the use of mobile phones to avoid longer duration of exposure to radio waves, as their bones are thin because of which the absorption rate is higher
Image Credit: Getty Images