Validation of short term recall of cell phone use
One of the challenges in epidemiological studies of the risk of cell phone use is the measurement of exposure i.e. the actual use of the phone by study subjects. Vrijheid and colleagues recruited 653 volunteers in 11 of the countries that participated in the Interphone study. Cell phone use was recorded by operators or by using software modified phones, and compared with recalled use 6 months later using the Interphone study questionnaire. Correlations between recalled and actual phone use were moderate to high. The kappa statistic showed moderate to fair agreement for both number and duration of calls. There was moderate systematic error and substantial random error in the recall by the users. The large random error would be expected to reduce the power of the Interphone study to detect an increase in risk of brain, acoustic nerve, and salivary gland tumours, if a risk exists.
Vrijheid M, Cardis E, Armstrong BK, Auvinen A, et al. Validation of
short term recall of mobile phone use for the Interphone study. Occup
Environ Med 2006;63:237-243.
For more, see "Research -Toxicological-Cancer Studies-Tumour growth and development".
Huang T-Q, Lee J-S, Kim T-H, Pack J-K, et al. Effect of radiofrequency
radiation exposure on mouse skin tumorigenesis initiated by 7,12-dimethylbenz(a)anthracene.
Int J Radiat Biol 2005;81:861-867.
Chauhan and colleagues exposed human cancer cells to RFR at 1.9 MHz frequency for 6 hours (5 minutes on, 10 minutes off). The average SARs were 1 and 10 W/kg. They assessed the expression of proto-oncogenes and of heat shock proteins and compared the results to sham and heat-shock controls.
There were no significant changes in the levels of the proto-oncogenes FOS, JUN, and MYC, or in the expression of Hsp27 or Hsp70, in response to the RFR exposure.
Reference: Chauhan V, Mariampillai A, Bellier PV, Qutob SS, et al. Gene expression analysis of a human lymphoblastoma cell line exposed in vitro to an intermittent 1.9 GHz pulse-modulated radiofrequency field. Radiat Res 2006;165:424-429.
A recent study also studied the effect of RFR on heat shock proteins, and in addition examined the effect on release of free radicals. Human monocytes were exposed for 60 minutes to RFR at 1800 MHz and SAR of 2 W/kg. No effect was seen on Hsp70 or free radical levels.
For more, see “Toxicological Experiments– others- heat shock response”.
Simko M, Hartwig C, Lantow M, Lupke M, et al. Hsp70 expression and free
radical release after exposure to non-thermal radio-frequency electromagnetic
fields and ultrafine particles in human Mono Mac 6 cells. Toxicology
Self-reported health complaints attributed to EMF exposure
A watchdog project was established in the Rhineland-Palatinate region of Germany for an 18-month period starting in October 2003. Extensive publicity was given to the project, and individuals were invited to self-notify if they deemed themselves to have symptoms related to exposure to electromagnetic fields (EMFs).
A total of 192 persons registered, and of these 56% classified themselves as being electromagnetic hypersensitive. Further studies on these individuals are planned. The authors emphasize that the responses cannot be used to estimate a population prevalence.
Schuz J, Petters C, Egle UT, Jansen B, et al. The “Mainzer-Wachhund”:
results from a watchdog project on self-reported health complaints attributed
to exposure to electromagnetic fields. Bioelectromagnetics 2006;27:280-287.
Study of individuals with symptoms on cell phone exposure
and colleagues studied people that reported being sensitive to cell
phone signals and compared them with controls. The "sensitive"
subjects developed symptoms during exposure to GSM signals, but also
to sham exposure. There was no significant difference between the two
conditions. In addition the “sensitive” subjects could not
accurately detect when they were exposed to the RFR. The authors suggest
that psychological factors may play a part in this condition.
For more, see "Clinical Experiments - others - General Health Complaints"