Today I saw a bunch of sensationalist headlines saying things like “Beware! Using your cell phone could lead to brain cancer” and “Risk of brain cancer can triple after 25 years of cellphone use, study finds.” Knowing that scientific reporting can be notoriously overblown, I wanted to dig into this new study to see what it actually said. And guess what? It’s not nearly as conclusive as these headlines would lead you to believe.
The Swedish study looked at the cell phone and cordless phone behavior of 1,380 people and compared it with the participants’ rates of developing malignant brain tumors. They reported that people who had used mobile or cordless phones for more than 25 years tripled their risk for gliomas, a certain type of brain cancer.
Sounds solid, right? What are the problems with this research? First, the data collected required people to remember their behavior patterns from decades earlier–something that humans are notoriously bad at doing. Do you remember how many hours per day you used your cell phone 20 years ago? Do you even remember what year you first got a cell phone or cordless phone? I don’t. Second, it is a correlative study, not a cause and effect study. There are no double-blind, randomized, controlled settings in which equally healthy, same aged groups of people were given cellphones and told to use them a certain amount of time per day and then compared to people who didn’t use cellphones. That would be a good design for a study on a topic like this. Looking backwards at self-reported data makes it incredibly hard to control for complicating factors, and it is not a great way to ensure accuracy of the findings.
The headlines also overstate the problem. Even if you “triple your risk” of brain cancer it is still incredibly unlikely you will develop it at all. Only about 5 in every 100,000 people will develop any kind of brain tumor, including gliomas, so tripling the risk would mean 15 out of 100,000 people would get it. So the risk is still very low.
I think the logical question is: what can the average person learn from a study like this, and how should it change their behavior? First, I would say not to panic, because even if the study results turn out to be true, the risk of brain cancer is still very low. Second, if the findings worry you, you can take reasonable and rational precautions recommended by neuroscientists, like limiting children’s time with devices at their ears, not sleeping next to your cellphone or cordless phone base, and/or using a hands-free device or speakerphone function. Finally, I would say to keep an eye out for further studies on this topic, because it’s clear that more research needs to be done to find a conclusive link.