Danish study shows no cancer risk
The much-anticipated study from Denmark (see November 1999 and April 2000 updates) has now been published. The cancer rates were studied in all cellular telephone subscribers and compared with expected rates, derived from the entire Danish population. There were no increased rates in the telephone users, either for overall cancer, or for specific cancer types, such as brain cancer or leukaemia. For further details of this article, see "Research - Epidemiology".
Robert Park, in an editorial in the same issue of the journal, comments on public perception of risk.
This is the third large epidemiological study on cell phones and cancer to be published in recent months - see the January and February 2001 updates for news of the studies by Muscat and Inskip.
References: Johansen C, Boice JD, McLaughlin JK, Olsen JH. Cellular telephones and cancer - a nationwide cohort study in Denmark. J Natl Cancer Inst 2001;93:203-207.
Park RL. Cellular telephones and cancer: how should science respond? J Natl Cancer Inst 2001;93:166-167.
In July 2000 we noted that a group of Finnish researchers had reported that RF radiation could affect the electroencephalogram (EEG) tracings during performance of an auditory memory task.
These authors have repeated their study on volunteers performing a visual memory task. For further details of these articles, see "Research - Clinical - EEG".
Krause CM, Sillanmaki L, Koivisto M, Haggquist A, et al. Effects of
electromagnetic fields emitted by cellular phones on the electroencephalogram
during a visual working memory task. Intl J Rad Biol 2000;76:1659-1667.
Claims have been made from time to time that RF radiation can produce genotoxic effects on cells - that is, genetic damage in the DNA that could predispose the cell to cancer formation. A new study reports that no such effects were seen in human blood cells that had been exposed to RF radiation at a cellular telephone frequency (835.62 MHz). The mean SAR was 4.4 or 5.0 W/kg. The paper by Vijayalaxmi and colleagues includes a useful summary of previous experiments in this area of research. Another paper by this group is summarised in the January 2001 "What's New".
Vijayalaxmi, Pickard WF, Bisht KS, Leal BZ, et al. Cytogenetic studies
in human blood lymphocytes exposed in vitro to radiofrequency radiation
at a cellular telephone frequency (835.62 MHz, FDMA). Radiat Res 2001;155:113-121.
While there have been some laboratory studies that have suggested that RF radiation can induce cancer, "the great majority of these studies have failed to demonstrate genotoxic effects" (Royal Society of Canada Expert Panel). Another study, by Roti Roti and colleagues, has also failed to demonstrate cancer transformation in cells exposed to RF radiation in the cell phone range. In a further experiment, the cells were first exposed to X-rays and then to the RF radiation. The cells showed no difference from controls in the rate of cancer transformation.
Reference: Roti Roti JL, Malyapa RS, Bisht KS, Ahern EW, et al. Neoplastic transformation in C3H 10T1/2 cells after exposure to 835.62 MHz FDMA and 847.74 MHz CDMA radiations. Radiat Res 2001;155:239-247