Could brain tumors cause heavy cellphone use?

The World Health Organization just released a massive 10-year study of cellphone users in 13 countries. The study, published in published in The International Journal of Epidemiology may raise more questions than it answers. For instance, it showed that one form of brain cancer is actually less frequent among all cellphone users than it is in the non-user population. However, it also found that those with the highest level of cellphone use had a 40 percent higher risk for a type of brain tumor called a glioma..

There may be a tendency to assign causality to the electronic device, but is that merited? Isn’t it equally possible that this particular type of brain tumor, in its early stages, causes sufferers to want to be incessantly on their cellphone—or that some as-yet-undiscovered brain anomaly that predisposes people to the tumor also predisposes them to want to yak forever on a cellphone? Will the WHO study cause you to alter your cellphone use in any way? If so, what will you change?