Study suggests risk of brain cancer not increased withshort-term cell phone use

Abstract

According to an article published in the December 20, 2000, issue of the Journal of the American Medical Association (JAMA 2000 2843001-7), the use of handheld cellular telephones does not seem to beassociated with the risk of brain cancer, but further studies are neededto account for longer induction periods, especially for slow-growingtumours. Joshua E Muscat and colleagues, of the American HealthFoundation, Valhalla, NY, conducted a case-control study from 1994 to1998 to test the hypothesis that using handheld cellular telephones isrelated to the risk of primary brain cancer. Four hundred sixty-nine menand women aged 18 to 80 years with primary brain cancer and 422 matchedcontrols without brain cancer took part in the study. Patients wereinterviewed at Memorial Sloan-Kettering Cancer Center, New YorkUniversity Medical Center, Columbia Presbyterian Hospital in NewYork, Rhode Island Hospital in Providence and Massachusetts GeneralHospital in Boston. According to background information cited in the study, there were morethan 86 million cellular phone users by the end of 1999. The use ofcellular telephones is one of several suspected risk factors for braincancer, although the causes of this disease remain poorly understood.The health effects caused by using cellular telephones are currentlybeing studied in a number of populations. In preliminary reports of acase-control study conducted in Sweden, the risk of brain cancer wasunrelated to using a handheld cellular telephone. Cellular telephones include handheld or mobile telephones, cartelephones, and portable or bag telephones that operate onradiofrequency (RF) signals in the 800-900 MHz range. Concerns havebeen raised about possible adverse health effects caused by exposure tothese signals. In particular, the concern that the use of handheldcellular telephones causes brain cancer is based on the close proximityof the antenna, which is incorporated into the telephone receiver, tothe head of the user. The authors used a structured questionnaire to interview patients. Thepatients were asked if they had ever used a handheld cellular telephoneon a regular basis. `Regular' was defined as having had a subscriptionto cellular telephone service. Information was obtained on the number ofyears of use, minutes/hours used per month, year of first use,manufacturer, and reported average monthly bill. Information on whichhand was used to hold the cellular telephone was collected from 700(78.6%) of the 891 patients. `The use of handheld cellular telephones was unrelated to the risk ofbrain cancer in the current study', the authors write. `The median monthly hours of use were 2.5 for cases and 2.2 forcontrols', they report. `Compared with patients who never used handheldcellular telephones, the multivariate odds ratio (OR) associated withregular past or current use was 0.85. The OR for infrequent users (lessthan 0.72 hours per month) was 1.0 and for frequent users (more than10.1 hours per month) was 0.7'. `The mean duration of use was 2.8 years for cases and 2.7 years forcontrols; no association with brain cancer was observed according toduration of use', they continue. The study found that among brain cancer cases, cerebral tumours occurredmore frequently on the same side of the head where cellular telephoneshad been used (26 versus 15 cases). But in cases of temporal lobe cancer, agreater percentage of tumours occurred in the opposite side of the head(9 versus 5 cases). The authors report the OR was less than 1.0 (i.e. no increase in risk)for all histologic categories of brain cancer except for an uncommontype of brain cancer called neuroepitheliomatous. `The current study shows no effect with short-term exposure to cellulartelephones that operate on (primarily) analogue signals', the authorsconclude. `Further studies are needed to account for longer inductionperiods, especially for slow-growing tumours. The RF fields emitted fromdigital cellular telephones might have different effects on biologicaltissue than analogue telephones, and studies are underway in severalEuropean countries that use primarily digital telecommunicationnetworks'.(This work was supported by a contract from WirelessTechnology Research LLC, and by grants from the Public Health Service,Washington, DC.)