Brain tumors and salivary gland cancers among cellular telephone users

Background. Possible risk of cancer associated with use of cellular telephones has lately been a subject of public debate, Methods. We conducted a register based, case-control study on cellular phone use and cancer. The study subjects were all cases of brain tumor (N = 398) and salivary gland cancer (N = 34) diagnosed in Finland in 1996, with five controls per case. Results. Cellular phone use was not associated with brain tumors or salivary gland cancers overall, but there was a weak association between gliomas and analog cellular phones. Conclusions. A register-based approach has limited value in risk assessment of cellular phone use owing to lack of information on exposure.