Why do many scientists around the world believe mobile phone use increases cancer risk?
woensdag, 23 juli 2014 - Categorie: Artikelen
Bron: www.saferemr.com/2014/07/why-do-many-scientists-around-world.html .
16 juli 2014
Given the international media attention generated by the City of Berkeley's proposed cell phone warning law, I have been questioned by journalists and others why I believe that mobile (cell and cordless) phone use increases brain cancer risk.
My colleagues and I published a meta-analysis on mobile phone use and tumor risk five years ago in the Journal of Clinical Oncology (Myung et al. 2009). When we grouped the 23 studies based upon the quality of the research, we found strong differences. In the thirteen studies which failed to meet scientific best practices, we found what appeared to be reduced tumor risk. However, in the ten higher-quality studies we found increased tumor risk among mobile phone users, especially in brain tumor studies. Increased brain tumor risk was generally found in studies where individuals had used mobile phones for ten or more years. The risk was stronger on the side of the head where people predominantly used their mobile phones.
Interestingly, the higher quality studies had no funding from the cellular industry, whereas the lower quality studies had at least partial industry funding.
In May, 2011, thirty-one experts were convened by the International Agency for Research on Cancer of the World Health Organization. After a review of the epidemiologic and toxicology research, the expert group classified radiofrequency radiation as ''possibly carcinogenic to humans'' (Group 2B carcinogen), largely based upon the epidemiologic studies of long-term mobile phone use.
Since 2011, several new, major epidemiologic studies have been published which provide further evidence that long-term mobile phone use is associated with increased risk of glioma, a type of malignant brain tumor, and acoustic neuroma, a nonmalignant tumor of the nerve from the ear to the brain. Moreover, the risks increase with the amount and duration of mobile phone use and are stronger on the side of the head where the mobile phone was predominantly used.
A careful review of the research strongly suggests that long-term mobile phone use increases the risk of glioma and acoustic neuroma. Furthermore, although more research is needed, there is some evidence that mobile phone may increase the risk of other head and neck tumors (e.g., meningioma and parotid gland tumors). Currently, many scientists in the U.S. and in many other nations share this belief. Some, however, will not express this belief publicly in order not to jeopardize industry funding for their research. Many researchers are funded largely by industry, and some are now conducting 30-year cohort studies.
Industry,of course, prefers we wait until these studies are concluded before governments issue precautionary safety warnings or alter public policies that regulate mobile phones and other wireless devices. This is a tactic that was used successfully for decades by the tobacco industry as well as other industries to delay regulation at the expense of public health.
See the three recently published review papers cited below for the supporting evidence that long-term exposure to the non-ionizing electromagnetic radiation emitted by mobile phones increases tumor risk.
Additional resources can be found on this Electromagnetic Radiation Safety website.
Hardell L., Carlberg M. Using the Hill viewpoints from 1965 for evaluating strengths of evidence of the risk for brain tumors associated with use of mobile and cordless phones. Rev Environ Health. 2013;28(2-3):97-106. doi: 10.1515/reveh-2013-0006.
Wireless phones, i.e., mobile phones and cordless phones, emit radiofrequency electromagnetic fields (RF-EMF) when used. An increased risk of brain tumors is a major concern. The International Agency for Research on Cancer (IARC) at the World Health Organization (WHO) evaluated the carcinogenic effect to humans from RF-EMF in May 2011. It was concluded that RF-EMF is a group 2B, i.e., a ''possible'', human carcinogen. Bradford Hill gave a presidential address at the British Royal Society of Medicine in 1965 on the association or causation that provides a helpful framework for evaluation of the brain tumor risk from RF-EMF.
All nine issues on causation according to Hill were evaluated. Regarding wireless phones, only studies with long-term use were included. In addition, laboratory studies and data on the incidence of brain tumors were considered.
The criteria on strength, consistency, specificity, temporality, and biologic gradient for evidence of increased risk for glioma and acoustic neuroma were fulfilled. Additional evidence came from plausibility and analogy based on laboratory studies. Regarding coherence, several studies show increasing incidence of brain tumors, especially in the most exposed area. Support for the experiment came from antioxidants that can alleviate the generation of reactive oxygen species involved in biologic effects, although a direct mechanism for brain tumor carcinogenesis has not been shown. In addition, the finding of no increased risk for brain tumors in subjects using the mobile phone only in a car with an external antenna is supportive evidence. Hill did not consider all the needed nine viewpoints to be essential requirements.
Based on the Hill criteria, glioma and acoustic neuroma should be considered to be caused by RF-EMF emissions from wireless phones and regarded as carcinogenic to humans, classifying it as group 1 according to the IARC classification. Current guidelines for exposure need to be urgently revised.
Levis AG, Minicuci N, Ricci P, Gennaro V, Garbisa S.Mobile phones and head tumours. The discrepancies in cause-effect relationships in the epidemiological studies - how do they arise? Environ Health. 2011 Jun 17;10:59. doi: 10.1186/1476-069X-10-59.
Whether or not there is a relationship between use of mobile phones (analogue and digital cellulars, and cordless) and head tumour risk (brain tumours, acoustic neuromas, and salivary gland tumours) is still a matter of debate; progress requires a critical analysis of the methodological elements necessary for an impartial evaluation of contradictory studies.
A close examination of the protocols and results from all case-control and cohort studies, pooled- and meta-analyses on head tumour risk for mobile phone users was carried out, and for each study the elements necessary for evaluating its reliability were identified. In addition, new meta-analyses of the literature data were undertaken. These were limited to subjects with mobile phone latency time compatible with the progression of the examined tumours, and with analysis of the laterality of head tumour localisation corresponding to the habitual laterality of mobile phone use.
Blind protocols, free from errors, bias, and financial conditioning factors, give positive results that reveal a cause-effect relationship between long-term mobile phone use or latency and statistically significant increase of ipsilateral head tumour risk, with biological plausibility. Non-blind protocols, which instead are affected by errors, bias, and financial conditioning factors, give negative results with systematic underestimate of such risk. However, also in these studies a statistically significant increase in risk of ipsilateral head tumours is quite common after more than 10 years of mobile phone use or latency. The meta-analyses, our included, examining only data on ipsilateral tumours in subjects using mobile phones since or for at least 10 years, show large and statistically significant increases in risk of ipsilateral brain gliomas and acoustic neuromas.
Our analysis of the literature studies and of the results from meta-analyses of the significant data alone shows an almost doubling of the risk of head tumours induced by long-term mobile phone use or latency.
Davis DL, Kesari S, Soskolne CL, Miller AB, Stein Y. Swedish review strengthens grounds for concluding that radiation from cellular and cordless phones is a probable human carcinogen. Pathophysiology. 2013 Apr;20(2):123-9. doi: 10.1016/j.pathophys.2013.03.001. Epub 2013 May 7.
With 5.9 billion reported users, mobile phones constitute a new, ubiquitous and rapidly growing exposure worldwide. Mobile phones are two-way microwave radios that also emit low levels of electromagnetic radiation. Inconsistent results have been published on potential risks of brain tumors tied with mobile phone use as a result of important methodological differences in study design and statistical power. Some studies have examined mobile phone users for periods of time that are too short to detect an increased risk of brain cancer, while others have misclassified exposures by placing those with exposures to microwave radiation from cordless phones in the control group, or failing to attribute such exposures in the cases. In 2011, the World Health Organization, International Agency for Research on Cancer (IARC) advised that electromagnetic radiation from mobile phone and other wireless devices constitutes a ''possible human carcinogen,'' 2B. Recent analyses not considered in the IARC review that take into account these methodological shortcomings from a number of authors find that brain tumor risk is significantly elevated for those who have used mobile phones for at least a decade. Studies carried out in Sweden indicate that those who begin using either cordless or mobile phones regularly before age 20 have greater than a fourfold increased risk of ipsilateral glioma. Given that treatment for a single case of brain cancer can cost between $100,000 for radiation therapy alone and up to $1 million depending on drug costs, resources to address this illness are already in short supply and not universally available in either developing or developed countries. Significant additional shortages in oncology services are expected at the current growth of cancer. No other environmental carcinogen has produced evidence of an increased risk in just one decade. Empirical data have shown a difference in the dielectric properties of tissues as a function of age, mostly due to the higher water content in children's tissues. High resolution computerized models based on human imaging data suggest that children are indeed more susceptible to the effects of EMF exposure at microwave frequencies. If the increased brain cancer risk found in young users in these recent studies does apply at the global level, the gap between supply and demand for oncology services will continue to widen. Many nations, phone manufacturers, and expert groups, advise prevention in light of these concerns by taking the simple precaution of ''distance'' to minimize exposures to the brain and body. We note than brain cancer is the proverbial ''tip of the iceberg''; the rest of the body is also showing effects other than cancers.
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