In addition, the study revealed no evidence of increasing risk with progressively increasing number of calls, longer call time, or years since beginning cell phone use.
此外，报告显示并没有证据表明致癌的风险会随着通话次数、时长以及使用手机年限的增加而增加。
2
Researchers found that a 50-minute call led to a localised increase in brain activity of 7%, but they said there was no evidence to suggest the rise was harmful.
In 2007, the American Medical Association decided not to call excessive video-gaming an addiction, saying there was insufficient evidence to warrant the label of a diagnosable disorder.