Cell phone and risk of brain tumors
A big number of the large studies that were conducted years ago were showing no real association between cell phone use and brain cancer
Notably, the Interphone Study by the International Agency for Research on Cancer was conducted in 13 countries and in 2011 did not find an increased risk of brain cancer from cell phone use.
Of note, research involving cell phone use is inherently hard to conduct.
So much of it relies on self-reporting. It also involves trying to directly measure the use of the cell phone while it's against the head. Other questions include whether the cell phone is pointed at another organ, how many hours a day the phone is directly against the head, and how long the phone has been used in that way.
There are experts who prefer animal studies because they argue that the epidemiological studies in people have limitations that may prevent researchers from seeing certain outcome.
The National Toxicity Program reported that its studies found that high exposure to RFR was associated with clear evidence of tumors in the hearts of male rats, as well as some evidence of tumors in the brains and adrenal glands of male rats.
Despite this, there are others investigators who continue to hold that what is seen in animal models does not reflect what is seen in humans.
Another area of study that hasn't been thoroughly examined is cell phone use in children. Children from a very young age now have exposure to cell phones and we don't have enough studies to know the safety of this procedure.