Dr. Elizabeth Cullen
Although it is less than thirty years since mobile telephones have come in to common usage in Europe, exposure to radio frequency radiation has increased substantially, with many sources of microwave radiation now operating in our environment. There are almost six thousand mobile telephone transmitter masts in operation in Ireland at present, and Irish people sent over 8 billion texts last year, twice the European average1. With such widespread exposure, even small risks to health may have a large impact on the population.
There are two schools of thought on how microwaves affect the human body. One is that microwave radiation only affects the body by heating it, while the second approach considers that microwave radiation may have additional impacts. It is important therefore to know which approach is correct. Exposure to non-ionizing radiation is governed internationally by guidelines issued in 1998, by the International Commission for Non-ionizing Radiation Protection (ICNIRP)2. These guidelines are used by national governments, including the Irish government to regulate levels of exposure to this radiation. These guidelines are issued on the basis that it is only the heating effects of such radiation that may result in adverse health impacts.
However, there is often insufficient data available to fully assess the impact of new technologies on health. In this situation, the precautionary principle may be useful. This principle may be invoked when three preliminary conditions have been met; namely that potentially adverse effects have been identified, the scientific data available is evaluated, and the extent of scientific uncertainty is ascertained.3 The impact of microwave radiation on health will now be discussed from these three perspectives.
In view of the continuous exposure of the population to microwave radiation, the identification of potential adverse effects is important. Children are particularly vulnerable, as their skull is thinner, with the absorption of radio frequency radiation twice as high as that of adults4. They also have a longer lifetime exposure.
There are many methodological problems however, inherent in identifying adverse health effects from microwave radiation. In particular there are great difficulties in assessing exposure Irish Doctors Environmental Association and individuals are not generally aware of the levels to which they are exposed. Levels of radiofrequency radiation depend on many factors, such as the type of telephone used, the distance from the base station, whether the user is in a car, or in the upper floor of a building, and the time of day. As a result, epidemiologic studies to date have relied on ‘rather crude proxies for exposure, such as job title, proximity to a base station or use of a mobile telephone5.
Notwithstanding such difficulties, it is not disputed that physiological changes occur at currently accepted safe levels of exposure. Such studies include statistically significant physiological changes observed in alpha and beta EEG waves6 and changes in non REM sleep in people exposed to radiation from mobile phones7. The question is whether such documented changes may impact adversely on health, and there is some evidence to support this; a significant increase in the risk of brain and parotid gland tumours was noted in users of mobile phones for over 10 years, more marked in the side of the body where the phone was most often used.8
There is also some evidence that people living near telecommunication masts may be affected. When compared to people living more than 300 metres from transmitters, people living closer to transmitters suffered significantly more frequently from symptoms such as tiredness, headache, sleep disturbance, depression, loss of memory, and dizziness.9 A recent analysis identified a total of 10 studies which examined health effects suffered by people living near mobile phone base stations. Eight of the 10 studies reported an increased prevalence of adverse neurobehavioral symptoms or cancer in populations living at distances less than 500 meters from base stations. None of the studies reported exposure above accepted international guidelines, suggesting that current guidelines may be inadequate in protecting human health.10
The ICNIRP guidelines acknowledge the methodological difficulties in ascertaining exposure levels, and since these guidelines were issued, three large studies were identified which investigated the relationship between exposure to microwave radiation and ill-health.
The REFLEX report was the earliest study, involved 12 research groups in seven countries and reported its findings in 2004. The researchers found evidence of toxic effects from radiation in the radiofrequency range, with DNA breakages, chromosomal aberrations and the formation of micronuclei in human fibroblasts. The degree of damage was dependent on the duration of exposure and on the type of signal used11. The researchers further stated that the impacts of such radiation on “molecular, cellular and sub-cellular mechanisms cannot be denied” 12. The SCENHIR report was issued by the European Commission in 2009. This study was unable to be definitive in its conclusions; while it stated that exposure to radiofrequency radiation was unlikely to lead to an increase in cancer in humans, it found that long term use may increase the risk of acoustic neuroma and further studies would be required, as “the widespread duration of exposure of humans to radiofrequency fields from mobile phones is shorter than the induction time of some cancers”. The report added that to date no specific study on children exists.
The third study, the Interphone study was undertaken by the World Health Organization and the International Agency for Research on Cancer13. It was the largest case-control study of mobile phone use and brain tumours, and was conducted in 13 countries over a 10 year period, and reported in 2010. This report found that there were suggestions of an increased risk of glioma, and less so of meningioma in people who had used their mobile phones most often, and on the side that they used the phone. It stated that “further investigation of mobile phone use and cancer is merited”.
It is clear that there is uncertainty in relation to adverse impacts of microwave radiation, and this is acknowledged in the ICNIRP guidelines themselves, which state: “There is insufficient information on the …health effects of EMF exposure of human populations …. to provide a rigorous basis for establishing safety factors over the whole frequency range and for all frequency modulations”. A simple Pubmed search in January 2011 using the words “health effects mobile phones”, revealed 328 articles published in the intervening 13 years since the guidelines were issued. Some findings included an association between the use of a mobile phone and the development of brain tumours, changes in lipid profiles among mobile phone users, a possible weak toxicity impact, no impact on sleep quality, little evidence of adverse impacts on neurobehavioural development in children, and no temporal trend in the incidence of brain cancer in the United States from 1992 to 2006. However, a substantial number of the papers reported that the results were qualified by the short time in which mobile phones have been used, and it is not surprising that the majority of these published reports, all called for more research to be undertaken.
In relation to the precautionary principle, for agents that are not drugs, pesticides or Irish Doctors Environmental Association food, European Community legislation states that “it is for the users, citizens or consumers associations to demonstrate the danger associated with a procedure or product after it has been placed on the market”14. In the case of the impact of microwave radiation on health, it is clear that the three criteria necessary for the adoption of the precautionary principle can be met.
Several simple straightforward precautionary measures may therefore be proposed: Warnings stating that the health effects of exposure to microwave radiation have not been fully established should be put on all mobile phones, and telecommunication masts should not be sited near schools and hospitals. Restrictions must be placed on the use of such devices by children under 12 years and women who are pregnant. An education campaign, encouraging people to be cautious with their use of such devices must be initiated and data on exposure to non-ionizing radiation should be included on all new entrants in the National Cancer Register
For preventive public health protection, a preliminary guideline level for exposure to microwave radiation of 0.017 microwatts per cm2 has been recommended15. This is equivalent to 0.00017 W/m2. The ICNIRP guidelines are 10W/m2, over 5,000 times higher.
Refinement of exposure assessment is critical to improved epidemiological studies, and a prospective cohort study, using the personal exposure meters as has been recommended must be initiated. As the country which records the highest use of this type of technology, and a young population, we have perhaps a greater responsibility to promote this type of research. The tragedy of avoidable illness is only superseded by the knowledge that it could have been avoided. There is an onus on public health professionals to take the lead. This is the time for the precautionary principle to come into action.