Do CellPhones Can Cause Brain Tumors?

It doesn't seem to make sense that cellphones should cause cancer. Because the radiation they emit is non-ionizing, which means it doesn't enough energy to rip electrons off atoms or molecules and destroy DNA. The radiation from cellphones is almost identical to the radiation inside a microwave. The wavelengths are almost the same, about 15 centimeters long. This led to various internet videos where cellphones were shown popping popcorn or cooking eggs, now that obviously IMPOSSIBLE because the amount of power in a microwave is over a thousand times the power of radiation of microwaves emitted from your cellphone.

So, would you be concerned about living near a cellphone tower?

The truth is, if you live in a area with better reception that means your phone has to emit less microwaves in order to transmit to the tower. So you're actually exposed to lower levels of microwaves radiation living near a cellphone tower than living far from it.

However there have been some scientific studies that show very high level microwaves like those from a mobile phone can cause heat shock proteins to be released inside the body, and it's thought that could be related to the onset of cancer. So perhaps there is a reason to study the biological effects of cellphones on people.

A recently published Swedish study found that cellphone users were 30% more likely to develop Glioma. Glioma is the most common form of malignant brain cancer and it gets worse, those people who'd use a cellphone for over 25 years had a three-fold increase in this type of cancer. The World Health Organization (WHO) actually classified cellphone radiation as possibly carcinogenic to humans, but now consider that brain cancer are exceedingly rare in any given year you have 3 in 100.000 chance of developing glioma. According to the Swedish study, long-term cellphone use can increase that risk up to 9 in a 100.000 chance. Still a very small risk, but a significant increase.

The ideal way to do the experiment, would be to perform a "Randomize Control Trial", which is where you get a group hundred of thousands or millions of people who don't use cellphones and randomly give half of them cellphones and force the other half to live without. Then follow them for 15 to 20 years and see how many in each group developed glioma, because of just how rare brain tumors are. And immediately you can spot the problem with this experimental design. Virtually, we know that everyone already had a cellphone, there are more mobile devices than people on earth, more people have access to a cellphone than to a working toilet.

So the next best way to do the experiment would be to perform a "Prospective Observational Study", in which you gather a group of people and follow them over period of decades, monitoring their cellphone use and then you find out how many develop glioma and correlate that with their cellphone usage. The problem is people who use their cellphones a lot may differ other ways than just their cellphone use, plus there's the problem of scale even if you followed around 50.000 people for 10 years you'd only expect to observe 20 gliomas case and that's not nearly enough to detect a difference between the groups.

So the third way to do the experiment is to perform a "Case Control Study", in which you collect a group of people who have brain tumors (those are the cases) and you find a demographically very similar group who don't have brain tumors (those are the controls). And then you ask them about their behaviors over the previous decade and see if they markedly between the groups. For example, do the brain tumor cases use their phones a lot more than the controls? The Swedish study was one of these large-scale case control studies. But there is a question about whether this study was methodologically flawed. In hindsight if you get a brain tumor you might remember using you phone more than you did, and if you don't have a brain tumor you might remember using it less. 

There have been  a few prospective studies completed including 1 in Denmark, using almost entire Danish population and records from their cellphone companies and they found no link between cellphone usage and incidence of brain cancer. Another prospective study using almost 1 million women in the UK, and again found no link of brain cancer.

Over the last 15 to 20 years almost everyone is used to mobile phone. So you can look at the actual brain cancer rates on the overall population and if there's a link you would expect that rates to going up, but it is not. If the result of Swedish study were correct then the rates of glioma would be more than 40% higher than they are. So it is EXTREMELY UNLIKELY that cellphones actually can cause brain cancer and if they do either the effects take decades to show or the increase in risk is very very low.

Source : [Veritasium]