December 2005

Hardell and colleagues report results of another study

Hardell and colleagues have published a number of papers based on two previous case-control studies on cell phones and brain tumours (see "What's New" for November '99, June '00, April and July '01, August and November '02, April '03, October '04, and June '05).

They have now reported the results of another study, based on 413 cases of benign brain tumour from two regions of Sweden. The cases were recruited during the period July 1, 2000, and December 31, 2003. The main finding in the adjusted analysis was a statistically significant risk for acoustic neuroma for users of analogue phones (OR = 2.1). This was based on 20 cases. There were no increased risks for meningioma in the various groups studied, in the adjusted analyses.

This paper adds to the growing confusion regarding the relationship between acoustic neuroma and cell phones. For more, see "Research - Epidemiology".

Reference: Hardell L, Carlberg M, Mild KH. Case-control study in cellular and cordless telephones and the risk for acoustic neuroma or meningioma in patients diagnosed 2002-20003. Neuroepidemiology 2005;25:120-128.


Another review of the genetic effects of radiofrequency radiation

Another review has been added to the growing list of publications that have examined the genetic effects of radiofrequency radiation (RFR). Like the others, this review concludes that, while the majority of studies report no increased genetic damage in laboratory experiments, some do. Verschaeve comments that "a workshop in 2002 concluded that further investigations by individual laboratories most probably will not add much to the discussion of RFR genotoxicity. Large, well coordinated, international collaborative studies involving participation of several experienced scientists are considered an alternative of uttermost importance. One such study is now being planned."

For more, see "Research - Toxicological experiments - cancer studies".

Reference: Verschaeve L. Genetic effects of radiofrequency radiation. Toxicol Appl Pharmacol 2005;207 (Suppl 2):336-341.

Four more genotoxic studies

Four other studies have examined different aspects of genotoxicity. Whitehead and colleagues examined the expression of the proto-oncogene Fos in an attempt to confirm the findings of Goswami and colleagues (1999), who found a small but statistically significant increase in Fos levels in cells exposed to RFR at SAR levels of 0.06 W/kg. Whitehead and colleagues used SAR levels of 5 and 10 W/kg, but failed to find any increase in Fos levels.

Gorlitz et al. failed to find evidence of increased number of micronuclei in cells of mice exposed to RFR for 2 hours a day for either 1 or 6 weeks. The whole-body SAR levels were up to 33.2 W/kg.

Lai and Singh repeated their earlier observations that exposure of rats to RFR at whole-body average SAR of 0.6 W/kg for 2 hours causes increases in DNA strand breaks in the rats' brain cells. Simultaneous noise exposure blocked the microwave-induced DNA damage.

Chang and colleagues found no evidence of genotoxicity in bacterial cultures exposed to 835 MHz RFR at a SAR of 4 W/kg for 48 hours.

For more, see "Research - Toxicological experiments - cancer studies".

References: Whitehead T, Brownstein BH, Parry JJ, Thompson D, et al. Expression of the proto-oncogene Fos after exposure to radiofrequency radiation relevant to wireless communications. Radiation Research 2005;164:420-430.

Gorlitz B-D, Muller M, Ebert S, Hecker H, et al. Effects of 1-week and 6-week exposure to GSM/DCS radiofrequency radiation on micronucleus formation in B6C3F1 mice. Radiation Research 2005;164:431-439

Lai H, Singh NP. Interaction of microwaves and a temporally incoherent magnetic field on single and double DNA strand breaks in rat brain cells. Electromagnetic Biology and Medicine. 2004;24:23-29.

Chang S-K, Choi J-S, Gil H-W, Yang J-O, et al. Genotoxicity evaluation of electromagnetic fields generated by 835-MHz mobile phone frequency band. European Journal of Cancer Prevention 2005;14:175-179.

Two papers on base station antennas

Two recent papers, both from Spain, addressed base station issues. Martinez-Burdalo and colleagues used a high-resolution human model to compute the Specific Absorption Rate (SAR) from electromagnetic fields in the near zone of antennas. They report that although averaged field values are below the reference levels, maximum 10g averaged SAR values inside the exposed body can exceed ICNIRP guidelines.

The other paper is an ecological study. Balmori compared the reproductive productivity of storks nesting within 200 meters of antenna with those nesting more than 300 meters from antenna. He found that the birds nesting close to the antenna had a significantly lower productivity than those further away. The author recognized that there could be other variables at work. He does not comment on the possible effects on human reproduction from the declining stork population!

For more, see "Base stations".

References: Balmori A. Possible effects of electromagnetic fields from phone masts on a population of white storks. Electromagnetic Biology and Medicine 2005;24:109-119.

Martinez-Burdalo M, Martin A, Anguiano M, Villar R. On the safety assessment of human exposure in the proximity of cellular communications base-station antennas at 900, 1800 and2170 MHz. Phys Med Biol 2005;50:4125-4137.

More on energy absorption in heads of adults and children

Different views have been published on whether RFR energy is absorbed to a greater degree in children's heads, in comparison to adults. This subject has been discussed in "What's New" in September '03, March '04, and April and July '05. Keshvari and Lang used MRI based models in their calculations of energy absorption at different radio frequencies. They conclude:

 


"Our study and most of the previous theoretical studies indicate that there is no systematic difference in the RF energy absorption between child and adult heads".

Reference: Keshvari J, Lang S. Comparison of radio frequency energy absorption in ear and eye region of children and adults at 900, 1800 and 2450 MHz. Phys Med Biol 2005;50:4355-4369.

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