Thank you

Hi all!

With this last post I want to thank all of you for your time and interesting comments on my subject. It is been my first experience with a blog and it has been suprising. Thanks to you I’ve learned new things on 3 different topics which were very interesting to read about.

Thank you and I wish you all the best with your master thesis!

See you soon!
Bart

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The opinion of an expert

I have been able to interview an employee from Option, a global leader in wireless connectivity, security and experience. In the follow paragraphs you can find a summary of his opinion regarding the existence of a relation between brain cancer and cell phone usage.

First of all he mentioned that scientist researching the matter are still not certain about the impacts of cell phone radiation on the human brain. But since they cannot guarantee there are no adverse consequences to the use of a mobile phone, operators, like Vodafone, have made their own limits which are lower than the European regulations. (Side note: The European SAR limit is 2 Watt/kg). This limit is applicable both for mobile phones and the network itself. By doing this the operators want to protect the users and, to be honest, to make sure that no one can blame them in the future if the radiation turns out the be harmful.

One of the major precautions mobile phone manufactures take, is making use of directional antennas. These antennas emit radiation in a certain direction which is oriented away from the head when the mobile phone is used for calling. The design of the mobile phone is made in such a way that the user does not handle a mobile phone conversely. Examples of these are the placement of the speaker and the ease of handling the mobile phone in the correct direction.

Furthermore he stated that the impact of the radiation on the human body is not the same in every body part. The limbs are less affected by radiation while more sensitive regions are the brains, intestines and genitals.

He also stated that the effects of the radiation emitted by the mobile phone are similar to those used in a microwave oven. But since it is still unclear what the (long-term) effects are on the human body unnecessary exposure should be limited. So until a clear conclusion can be made on the effects of the radiation of mobile phones the following things should be avoided:

  • Sleeping with your mobile phone under your cushion
  • Keeping your mobile phone in your pocked
  • Using the mobile phone for long calls
  • Using the mobile phone in environments with low reception

He acknowledges the importance of mobile phones these days and that it is very convenient to keep your mobile phone nearby but that since there is still no scientific consensus exposure should be limited. But overall he does not seem to be too concerned since he keeps his mobile phone in a handy holder on its belt.

Preventive measures

A lot of protective measures against the harmful radiation of cell phones can be found online. An example of these measure can be found in the video below.

Most of these preventive measures can be narrowed down to the following simple rules:

  • Limit the amount of calls to the strict minimum
  • When calling use a hands-free system (not a blue-tooth head-set, because this does not eliminate the cause)
  • Keep the mobile phone away from the body (radiation decreases exponential with increasing distance)
  • Children should not use cell phones

National health organizations from several European countries have advised their citizens to follow the above rules in order to protect their own health. The necessity of these precautions is still unclear but the national health organizations use the precautionary principle.
This principle states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking action.

Some protective shielding casings and other devices that protect you from the harmful radiation  are also offered online, with doubtful proof of their effectiveness. One of these manufacturers is called GIA Cell Guard™ but a large variety of suppliers and products exist.

 

Sources:

http://en.wikipedia.org/wiki/Precautionary_principle
http://www.youtube.com/watch?v=b3PWiSQbXJs
http://www.cellphone-health.com/
http://www.emf-health.com/articles-10tips.htm

Expert agencies

So far I’ve been focusing on the literature and the scientific evidence, or better the lack of scientific evidence.

In this next post I’ll present the positions of several expert agencies.

The international Agency for Research on Cancer (IARC) is a member of the World Health Organization (WHO). Their mission is cancer research for cancer prevention. The published the following, I quote: “Lyon, France, May 31, 2011 ‐‐ The WHO/International Agency for Research on Cancer  IARC) has classified radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer 1, associated with wireless phone use.” – end quote.
The 2B classification implies that there could be some risk associated with the use of wireless telephones.

The National Toxicology Program (NTP) has not classified cell phones as having cancer-causing potential. The organization is still running tests on animals since they claim more tests are needed.

The Center for Disease control and prevention (CDC) recognizes that there are some studies that do raise concern. But they state that when all the research is taken together there is no indication for a significant association between cell phone use and health effects.

Altogether it seems that most of the organizations follow the opinion of the WHO or are still investigating whether or not there are health risk to the use of cell phones. But even the WHO is not clearly stating that there are risks involved. This emphasizes the uncertainty of the scientists conducting research on this topic.

In my opinion the clearest answer will be given by history. In a few decades when the data for brain cancer and global cell phone usage can be compared for a longer period of time it will be clear whether or not there is a relation between cell phone use and brain cancer.

 

Main sources:

The IARC: http://www.iarc.fr/
The American Cancer Society: http://www.cancer.org/
European cancer organization: http://www.ecco-org.eu/
National Toxicology Program: http://ntp.niehs.nih.gov/
Center for Disease control and prevention: http://www.cdc.gov/
U.S. Food and Drug administration: http://www.fda.gov/default.htm

Laboratory Data

Since the call for laboratory data was high I looked further into this matter. I can only say that as with anything else with this topic, a big controversy exists. Although in contradiction to most of the earlier findings that there is no relation between brain cancer and cell phone usage, it seems that there is a link between DNA damage and RF signals. For example:

The American Cancer society states that: ‘Experiments in the lab have shown that direct RF waves, which are given off by cell phones, have not enough energy to damage DNA directly. This has been supported by several studies carried out in the lab.’

On the other hand a study from January, 2012 by Cogulu et al. has shown that: ‘Cell phones which spread RF may damage DNA and change gene expression in brain cells.’ During this study brain cells of mice were exposed to RF signals and a SAR (Specific absorption rate) of 0,725/Kg for 6 hours in 3 days at 25°C.

Already earlier there were studies showing that RF waves could affect the DNA in brain cells. For example a study by Lai and Singh in 1997 showed that DNA damage occurred in rat brain cells after exposure to RF waves.

This contradicts the most studies stating that there is no relation between brain cancer and cell phone usage. Since I have not found any conclusive data regarding humans there is always room for questions like: ‘are the effects on human brain cells the same?

More information on SAR can be found here: http://en.wikipedia.org/wiki/Specific_absorption_rate

Sources:

American Cancer Society, http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/AtHome/cellular-phones

Cogulu et al., 2012, http://rd.springer.com/article/10.1007/s11060-011-0644-z#

Reaction

Hello everyone,

I am back! It has been a while but due to the exams I did not have the luxury to leave any comments or posts.

To make a small summary about the things you people pointed out regarding my earlier post:
-Is brain caused by cell phone usage or by other factors?
-Is the way that the cell phone is used important?
-Could the experiment be adjusted to get better results?

Below I’ll give an answer to these question .

 

Is brain caused by cell phone usage or by other factors?

This first question pretty much summarizes the whole topic of this blog. If a clear answer to that question existed the whole point of doing research regarding this topic would not be needed. But since researchers are still conducting studies regarding this it seems that there is no conclusive answer yet.

It seems that the general evidence points us into the direction of the non-relation between cell phone usage and brain cancer since only a group in Sweden was able to show a link between cell phone usage and brain cancer.

It should be noted that I did not look into the clients ordering these studies. If they would be somehow be linked by cell phone manufacturers then there would be a chance that the data would be “optimized”.

 

Is the way that the cell phone is used important?

I did not find any information regarding the details of the cell phone usage regarding brain cancer. But I think a fairly logic answer is available.

When a cell phone is in standby it stays in touch with the cellular network which is provided by a mobile phone operator. Therefore its location is known at any time as long as the cell phone is turned on. The signal emitted during standby is weak and therefore does not ask that much of the battery. In most cases during standby the cell phone will not be next to someone’s head. Since the intensity of the radiation drops significantly with increasing distance I do not think that this type of cell phone ‘usage’ would be the main source, even when taken into account that the standby time is much greater than other types of cell phone usage.

When sending a text message, a short, strong signal is generated to transfer the data of the text message. The frequency of this happening only depends on the amount of text messages a user would send in a day. But again, during the sending of the text messages the cell phone would not be directly next to the head and therefore the intensity of the radiation drops significantly.

During calling by cell phone a strong signal is generated over a longer period of time depending on the duration of the call itself. The prove for the stronger signal can easily be found in the drainage of the battery during calling. Cell phone manufacturers also mention by pointing out the difference between standby time and talking time.

During a call the cell phone, unless someone would be using a headset, is in direct contact with the head. So if there would be a main cause for brain cancer by cell phone usage it would be due to calling. A strong signal in combination with close contact to the head would be have the biggest impact if there is an impact at all.

Could the experiment be adjusted to get better results?

Measuring the broadcasting power of a cell phone would give a good idea about the signal strength of the cell phone but nothing more. The same kind of data would be generated by comparing different cell phones regarding their signal strength and power consumption over a certain period of time.

A better setup would be to bring living tissue in contact with radiation similar to the radiation emitted by cell phones for a prolonged period of time. But even so the conditions of the experiment are difficult to determine. For example:

What is the average cell phone usage?

What is the average emission of a cell phone?

What is the effect of the prolonged exposure to radiation due to standby time?

What is the effect of keeping a cell phone in a purse or in the pocket?

As you can see many different factors are affecting the potential outcome and the significance of the experiment. It is therefore not as easy to conduct an experiment that would generate data making a clear conclusion possible.

Also the questionnaire used to collect the data has a great impact on the answers. Depending on the way the question is formulated someone would give different answers resulting in wrong conclusions.

 

I do agree that the researchers should look into the data collecting method. If people are questioned about their cell phone usage over the last decade it is more than likely that the answers will be twisted since most people are not able to remember every detail of every day from the last decade. Maybe keeping a ‘cell phone diary’ would improve the reliability of the collected data although it seems quite unlikely everyone in the study group will fill in this diary correctly for as long as a decade.

 

As you can see there are many uncertainties regarding this topic. Several people are convinced about the existence of a relationship between brain cancer and cell phone usage but at least as many people are convinced of the opposite. The general public knows about this controversy and since there is no conclusive answer everyone has to decide for itself. Since the popularity of the cell phone keeps rising and new types, like the smart phone, are developed, I do not think that people would stop using the cell phone even if there would be a small increase of the risk regarding brain cancer.

 

The future will tell who is right and who is wrong.

The origin of the discussion

Many studies have been carried out trying to confirm or refute a relation between cell phone usage and brain cancer. Most studies are done by means of case-control. People diagnosed with brain cancer are asked for their cell phone use in the previous years which is compared by the cell phone use of people without brain cancer. The largest case-control study has been carried out in 13 countries under the name of INTERPHONE. The researchers compared the cell phone usage of more than 5000 people who developed brain tumors with a similar group of people without tumors. This study did not found a link between brain tumor risk and the frequency of calls or the duration of calls or cell phone use for 10 years or more. But the findings were difficult to interpret because of some people reporting implausibly high cell phone use. Therefore the researchers noted that due the shortcomings of the study it prevented them from drawing any firm conclusions.

Another type of study has been performed in Denmark between 1982 and 1995. More than 420000 people were followed in time regarding their cell phone use. The benefit of this type of study is that it does not rely on peoples memories and therefore is thought to be stronger than a case-control study. The results of this study are similar to those found in the INTERPHONE study but there are still limits as to how well this study might apply to people using cell phones today. At that time cell phones tended to require more power but people also probably used the phones less than they do today.

So although these studies cannot find a link between cell phone use and brain tumors it is unlikely that they will end the controversy due some limitations. Since cell phones are in widespread use for less than 20 years in most countries, it is not possible to rule out future health effects. Secondly, cell phones from 10 years ago are very different from the ones which are being used today. Additional studies have focused on adults rather than children and today cell phone use is widespread, even among young children. Finally, the measurements on cell phone use is mostly based on case-control studies which has known limitations.

On the other hand, several studies published by the Hardell group in Sweden report increased risk of tumors, particularly with 10 or more years of cell phone use. These results could not be found in other studies. Since there is no overall increase in brain cancer in Sweden during the years that correspond to these reports it is hard to know what to make of these results.

References:

Christoffer Johansen et al., Cellular telephones and cancer-a nationwide cohort study in Denmark, 2001, Journal of the National Cancer Institute, Vol. 93, No. 3, 203-207

Vini G. Khurana et al., Cell phones and brain tumors-a review including the long-term epidemiologic data, 2009, Surgical Neurology, 72, 205–215

Lennart Hardell  and Michael Carlberg, Mobile phones, cordless phones and the risk for brain tumours, 2009, International Journal of oncology, 35,  5-17

American Cancer society, 4/12/2011, http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/AtHome/cellular-phones

What is causing all this commotion?

Before I’ m going to discuss the relation between cell phone usage and brain cancer, I’ll give a brief introduction on cell phone history and technology. The following is based on the work of Vini G. Khurana et al. which they published in 2009 in Surgical Neurology.

Cell phones have been mass deployed since the mid 1990’s in most countries. At that time the 2G network was the standard, nowdays the 3G network is used which is based on adaptations of code division multiple access, or CDMA, and time division multiple access, or TDMA (800 and 1900 MHz). Like inionisating radiation it is the energy of the radiation that is responsible for its possible harmfullness. This energy is reflected in the power outputs of the radio waves of the cell phones.

Copyright Vini G. Khurana et al., 2009

Modern GSM handsets have a peak power of 1 to 2 W, whereas other digital celular technologies have power outputs of below 1 W, levels generally regarded as being safe by international regulatory authorities.

Trough “adapitive power control”, the power generated by a cell phone can vary during a conversation according to the amount of interference with the signal. This can happen when the user is in a moving vehicle or within a building or elevator. During handovers, the moment at which the user moves from one geographic arae to another, the signal interference is generally at its greatest and therefore the power output at its highest. The output power of the new 3G is measured to be between 0.25mW and 12mW depending on the cell phone model.

The power output of GSM antennae are far greater than cell phones and are associated with transmitter powers of 10 to 100W. In urban areas antennae use less power on average than in rural areas. In this latter one the base power output is much higher because of the vast areas requiring coverage between sparsely distributed base stations and cell phones rurraly are more often at their maximum power output during use in order to maintain good communication.