Do mobile phones cause cancer?

Executive Summary

We still do not know if mobile phone usage causes cancer. However, a hypothesis, based on recent data is claiming that mobile phones don’t cause cancer, but if something else triggers a cancer, the phone radiation can make the cancer grow faster.

Until the verdict is clear, it is better to follow some common–sense precautions: use a pair of headphones; in low signal areas and moving vehicles, keep phone conversations brief or resort to text messages; and keep the phone away from head when dialing a call out or sleeping.

Read the full article to learn about co–carcinogenecity, transmission tower radiation issues, and confirmed side effects of mobile phone use.

The linkage between cancers and mobile phone usage has been tested since 1985. The results are unclear even today. Some studies show an effect, while others find no effect at all.

The evidence so far

Some animal studies have shown an increase in cancer on exposure to mobile radiation. And some other animal studies have found no difference. So, the evidence has been equivocal in animal studies. Some scientists use these studies to claim that mobiles can cause cancer.

In humans, there is only a little increase in the incidence of brain tumours over the last 1–2 decades. During this time, the mobile usage has exploded multi–fold. Some researchers use this evidence to claim that mobiles do not increase the risk of cancer.

Limitations

One objection to relying on such studies is that brain tumours develop slowly, sometimes taking a decade or two. However, most of the mankind has not been using mobiles for two decades. So, we cannot assume that all brain cancers that could have been caused by mobile phones, have grown large enough to be detected.

Also, these human studies are observational in nature. They cannot decipher a cause–and–effect relation between mobile usage and cancers.

One solution is to perform a case–control study. For that, we would need two groups of human beings with similar socioeconomic characteristics, with one group that uses mobiles, and the other that rarely uses mobiles. The latter will be very difficult to find in the current world.

New hypothesis

Some other animal studies found something interesting. If you take some rats, expose them to some cancer–causing substance and then, add mobile radiation on top of it, their cancers increased substantially. In other words, the mobile radiation made their cancers grow faster.

Co–carcinogenecity

In other words, mobile radiation acted as a Co–carcinogen. It was not a carcinogen itself —it did not cause cancer by itself. However, if there was something else that triggered or initiated a cancer, then mobile radiation caused that cancer to grow faster.

So, the new hypothesis is that mobile radiation is not a carcinogen but a co–carcinogen.

In human beings, as per the hypothesis, it will not create new cases of brain tumours. But, it will accelerate those cases where something else has initiated a brain cancer.

To test this co–carcinogen hypothesis in humans is even more difficult than testing the carcinogen hypothesis.

The researchers would need to conduct a case–control study with two similar groups of people: one with something that causes cancer and uses mobile; another with something that causes cancer and does not use mobile.

Two such obvious groups are smokers, who risk lung cancer; and sunbathers, who risk skin cancer. Now, we just need to find a group of smokers, or beach–goers, who don’t use mobile phones!

To learn more about this interesting hypothesis, read: Do mobile phones give you brain cancer?

Some scientists have objection to this hypothesis. To read their objections, read on Medscape: Do Cell Phones Cause Cancer? Maybe Yes and No.

National Cancer Institute has a detailed document, and research paper links, about the cancer risk due to mobile phones. Read: Cell Phones and Cancer Risk.

Mobile radiation

Mobile phones communicate using radio frequency (RF) electromagnetic waves.

Electromagnetic waves are of different frequencies. The higher the frequency, the more is the wave energy.

Note that this energy is different from the energy of the radiation itself. The energy of the entire radiation comes from the amplitude, or the magnitude, of the wave. The energy of each small part of the wave, called a photon, comes from its frequency.

To understand the difference, think of a machine that shoots tennis balls at you. However hard the ball is thrown, it is still a tennis ball. This is like a low–frequency wave.

On the other hand, if the same machine starts shooting hard golf balls at you, it will be equivalent of a high–frequency wave.

For a low–frequency wave, or tennis balls, to cause serious damage, they will need to be thrown with very high velocities. For a high–frequency wave, or golf balls, a gentle throw is enough to break a glass window, or your head.

Enough of Physics!

Ionising versus non–ionising radiations

The higher frequency radiations such as x–rays and cosmic rays have high energy and are called ionising radiations. When such radiation hits any object, some atoms and molecules in the material turn into ions, or charged particles. Such ions, if formed in a living tissue, can damage the DNA in it.

Altered DNA is a recipe for cancer. That is why exposure to x–rays can cause cancer, even at low intensities.

The mobile radiation is lower in frequency. So their waves are non–ionising types of radiation. That does not mean that they won’t cause cancer. It just means that the chances of them causing cancer are much lower than their ionising counterparts.

At high enough intensities, non–ionising radiations also can cause damage, just like a high speed tennis ball can.

Thus, by nature, mobile radiation is not considered cancer–causing, or carcinogenic. However, we need a more conclusive proof to rule that possibility out.

Mobile handsets send low intensity radiation that is captured by antennas on mobile tower base stations. The base stations emit a much higher intensity radiation all around that can be captured by mobile phones within a certain radius around the base station.

While mobile tower antennas emit a much stronger signal than mobile phones, they are relatively away from human bodies. So their radiation faced by humans is low.

Mobile tower antenna radiation

1. Only the small antenna mounted on the tower emits radiation. The whole tower structure does not emit anything.
2. Usually, the antenna emits radiation in all horizontal directions. It does not emit radiation vertically down. So, if a mobile tower is installed on top of a building, the people staying inside the building are not blasted with radiation.
3. The intensity of radiation drops as an inverse square law. That is, the radiation 2 meters away from the antenna is 2 x 2 = 4 times less powerful than that 1 meter away.
4. To get dangerous amount of radiation from a tower antenna, you have to be almost touching it.

Mobile handset radiation

There is no direct evidence of mobile phone usage causing memory loss, brain damage, or foetal damage. However, here are some symptoms observed after prolonged use:

• Mild fatigue;
• Small and temporary increase in blood pressure during phone usage;
• Brain warming. This is found to disappear as soon as the phone is taken away from the head. The heating is more pronounced in small children. This is assumed to be because of smaller bone thickness of children’s skulls, in which the brain resides.

Incidentally, while we are discussing the medical risk to children from mobile phone usage, here is an article on this website about how mobile phones harm academic performance of children.

Finally, those videos on social media, where people make popcorns from corn kernels, by exposing them to a couple of mobile phones, are completely fake.

Precautions to reduce mobile radiation

Till things get clearer, if you use mobile phones a lot, it does not harm to take some common–sense precautions:

1. Use a pair of headphones, instead of speaking into the handset itself.
2. If you have to use the handset, keep the conversation brief.
3. Use text messages or chats, instead of telephoning, when possible.
4. If you move the phone 2 feet from your head, the radiation exposure to the head drops by 99%, compared to that when it is touching your ears. So, don’t keep the phone close to your head when sleeping.
5. When you are in a low–signal area such as inside a building or an elevator, the incoming mobile signal strength will be weak. So, your mobile will try to transmit at a much higher power than normal. Use the handset sparingly in such areas.
   You can check the incoming signal strength from the bar indicators shown at the top of your mobile screen.
6. If you are in a moving vehicle, your phone moves in and out of a transmission tower’s coverage area. It will hop from one tower to another. While that will appear seamless to the caller, the phone increases its transmission power during this switch. Reduce direct handset usage while in a moving vehicle.
7. The iPhone guide says that you should hold the phone half an inch away from the body when a call is dialed. A mobile phone transmits at a higher power than normal when it dials a call out.
   Don’t hold the handset to your ear before it is connected (that is, while the dial tone is ringing). Use speakerphone or headphones, when you are dialing out.

First published on: 26th August, 2016

Image credit: FOX from Pexels