BEIJING, March 26 (Xinhuanet) -- Cell phone use does not appear to be associated with an increased risk of glioma -- the most common type of brain tumor, according to news report on Sunday.

    The story may be different, however, for intense use of cell phones over many years.

    Public concern has been expressed about the possible adverse health effects of mobile telephones, mainly related to (brain) tumors," Dr. Anna Lahkola, of the Radiation and Nuclear Safety Authority, Helsinki, and colleagues explain in the International Journal of Cancer.

    The researchers examined the relationship between mobile phone use and risk of glioma by studying 1,521 glioma patients and 3,301 controls.

    The vast majority of both groups reported using cell phones. Overall, 92 percent of glioma patients and 94 percent of controls reported ever using a mobile phone.

    There was no evidence of increased glioma risk related to regular mobile phone use.

    There were no significant associations observed with duration of use, years since first use, cumulative number of calls, or cumulative hours of use.

    No increased glioma risk was observed when analog and digital phones were analyzed separately.

    There was, however, a trend toward increased risk of glioma in people who used a cell phone for more than 10 years exclusively on one side of the head, which was on the same side as the tumor. The association reached "borderline statistical significance."

    "This may be due either to chance or causal effect or information bias, i.e., overreporting of mobile phone use on the affected side by the cases with brain tumors," the investigators comment.

    (Agencies)