Health effects from mobile phone radiation
The increasing use of mobile phones has resulted in increased human exposure to radiofrequency electromagnetic fields: already more than 80% of the Finnish population have a mobile phone. Although the electromagnetic fields from mobile phones are weak, the high number of exposed persons, together with some provocative but inconclusive scientific results, has raised concerns about possible health hazards. Finnish universities and research institutes have investigated possible health effects of mobile phones in a national research programme. The results of this programme will be reported in a seminar held in Helsinki on 17 October, 2003.
The national research programme was carried out in two parts during the years 1998-2003, and was coordinated by the University of Kuopio (Prof. Jukka Juutilainen). The other participantes were STUK – the Radiation and Nuclear Safety Authority, Technical University of Tampere, University of Turku, Finnish Institute of Occupational Health and VTT Information Technology. The main source of funding was TEKES (National Technology Agency; a governmental organisation). The programme was also supported by Nokia, Benefon, Sonera, Elisa, Radiolinja, Finnish 2G, Mobile Manufacturers Forum and GSM Association.
The first part, ”Electromagnetic Fields from Mobile Phones as a Possible Health Risk” was conducted in 1998-2000. This first part of the programme included 6 research projects:
Project 1: STUK designed, constructed and tested two waveguide exposure chambers for cell culture experiments and designed an exposure chamber for animals. The equipment developed in the project have been used for biological experiments by the STUK and the University of Kuopio in the National Research Programme and in EU-funded research projects.
Project 2: The University of Kuopio studied the possibility that radiofrequency electromagnetic fields enhance cancer development. Skin tumors induced by UV radiation were used as the experimental model. Small differences were observed between the experimental groups, but the study did not show statistically significant effects on tumor development.
Project 3: STUK and University of Kuopio carried out experiments with cell cultures – the project tested different cell lines and methods to identify suitable models for investigating biological effects of electromagnetic fields. According to the results, relatively weak electromagnetic fields may cause cellular changes that are consistent with a stress response.
Project 4: The Finnish Institute of Occupational Health conducted a feasibility study for evaluating the association of cellullar phone use with brain and salivary gland cancers. About 400 brain tumors and 34 salivary gland cancers were identified from the Finnish Cancer Registry. Both case-control and cohort designs were studied but neither of the study designs could be regarded feasible enough at the time of the study, since the percentage of phone users was low.
Project 5: The Finnish Institute of Occupational Health studied possible symptoms caused by mobile phone RF fields on hypersensitive persons. 20 volunteers participated, and both analogue (NMT, 900 MHz) and digital phones (GSM 900 and 1800 MHz) were used as exposure sources. Variety of subjective symptoms or sensations were experienced by the test persons but the symptoms and sensations were not related to the exposure condition (true or sham exposure). None of the test persons could distinguish correctly RF exposure from sham exposure.
Project 6: VTT simulated by using dosimetric computer models the exposure of laboratory animals and cell cultures in the chambers developed in Project No. 1. The objective of dosimetry is to find out the “dose” (i.e. the power absorbed from the electromagnetic field) in cells and laboratory animals. This information is essential in order to proportion the results to exposure of a human using a mobile phone. Also the modelling method itself was studied.
The second part, “Health Risk Assessment of Wireless Communication” was carried out during the years 2000-2003. The second part of the programme included ten projects:
1. The effects of radiofrequency electromagnetic fields on cognition and brain function
2. Human circulatory responses during exposure to radiofrequency wireless communication
3. Effects of cellular phones on cardiac pacemakers
4. Activity of the enzyme ODC in cell cultures following RF exposures at 835 and 900 MHz
5. Budding yeast (Saccharomyces cerevisiae) as a model organism for studying the biological
effects of radiofrequency fields
6. Development of in vitro dosimetry and biomarkers to study in vivo RF-EMF biological effects
7. Dynamic adaptive modelling of the human body for radiofrequency radiation absorption
8. Numerical simulation of RF exposure conditions by the FDTD method
9. Case-control study of brain tumor etiology
10. Possible health effects of electromagnetic fields from mobile phones on hearing and balance
The following results (among other things) were obtained in these 10 projects:
· Centre for Cognitive Neuroscience (CCN, University of Turku) examined the effects of mobile phone on brain electrical activity (EEG), short-term memory and attention (cognitive functions), brain blood flow and metabolism, and subjective symptoms both in adults and children (10-14 years). According to EEG studies (3 studies) mobile phone appears to influence brain electrical activity in both adults and children. On the basis of the results from our other studies (7 studies), mobile phone does not affect cognitive functions, brain blood flow or metabolism, or subjective symptoms in adults or children.
· The effects of radiofrequency radiation on ODC activity, cell proliferation, and programmed cell death in yeast cells and cultured rodent cell lines were studied at University of Kuopio. The ODC activity was not clearly affected by different radiofrequency exposure levels or durations. However, our results showed some cell type specificity in radiofrequncy effects on ODC activity. More profound effects were found if cells were coexposed to a known stress factors (e.g. ultraviolet radiation, serum deprivation, or oxidative agents) together with radiofrequency fields. In summary, effects of mere radiofrequency radiation on different cell culture models are quite minor but various coexposure approaches warrant additional studies.
· STUK developed further technical methods for exposing cells to GSM mobile phone radiation.The objective was to improve the accuracy in the determination of the power absorbed (SAR) and the temperature rise in cell dishes. The SAR distribution and the temperature rise in the dish was determined by computing with numerical models and by measuring the electric field and the temperature rise in cell dishes. Measurements were carried out with specially constructed sensors.
· Biological studies showed that radiofrequency modulated electromagnetic fields (GSM 900MHz and GSM 1800 MHz) induced a stress response in the cells. In addition, there were changes in the expression and cellular localization of cytoskeletal proteins. These results support previously presented hypotheses of potential changes in the blood-brain barrier.
· Tampere University of Technology, Ragnar Granit Institute has developed anatomical models for estimation of radio frequency absorption dosimetry. Bone, brain tissue etc. have different intrinsic properties to absorb electromagnetic fields. To construct accurate computational models of the head for example the tissue compartments have to be identified. The basis for this is a stack of medical MR images of which certain anatomical tissue structures are identified. During the project a number of head and thorax models were formed
· VTT continued the dosimetric simulations started in the previous project by using expanded and detailed dosimetric computer models of the exposure chambers for laboratory animals and cell cultures.
More information: Prof. Jukka Juutilainen
Tel. +358 17 163226,050 590 3864 e-mail: firstname.lastname@example.org
(From Monday, 20 October; not available during the seminar)
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