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     Cell phone use does not appear to be associated with an increased risk of glioma（神经胶质瘤）— the most common type of brain cancers, according to new study. The story may be different, however for intense use of cell phones over many years. "The public are concerned about the possible negative health effects of mobile telephones," Dr. Anna Lahkola, of the Radiation and Nuclear Safety Authority, Helsinki, and his colleagues explain in the International Journal of Cancer. The researchers examined the relationship between cell phone use and risk of glioma by studying 1,521 glioma patients and 3, 301 controls（比照实验对象）.
     The vast majority of both groups reported using cell phones. 92 percent of glioma patients and 94 percent of controls reported ever using a cell phone. Overall, there was no evidence of increased glioma risk related to regular cell phone use. There were no significant associations observed with duration of use, years since first use, the total number of calls or the total hours of use. No increased glioma risk was observed when digital phones and other kinds of phones were analyzed separately.
     There was, however, a trend toward increased risk of glioma in people who had used cell phones for more than 10 years exclusively on one side of the head, which was on the same side as the cancer. This may be due to chance, causal effect（因果关系） or too many reports of cell phone use in cases with brain cancers the investigators commented.