Electromagnetic fields and public health: WHO
1 like496 views
Mobile phone use has risen dramatically globally with over 4.6 billion subscriptions. To date, no adverse health effects have been established from mobile phone use, but studies are ongoing to assess potential long-term effects. Guidelines for safe exposure to electromagnetic fields from mobile phones have been set based on assessments that tissue heating is the main interaction mechanism, and that risks below levels causing heating are unlikely. Further research is still needed due to increasing use and longer lifetime exposure.
Electromagnetic fields and public health: WHO
- 1. Fact sheet N°193 May 2010 Electromagnetic fields and public health: mobile =hones Key facts • Mobile phone use is ubiquitous with an estimated 4.6 billion =ubscriptions globally. • To date, no adverse health effects have been established for =obile phone use. • Studies are ongoing to assess potential long-term effects of =obile phone use. • There is an increased risk of road traffic injuries when drivers =se mobile phones (either handheld or "hands-free") while driving. =/LI> Mobile or cellular phones are now an integral part of modern telecommunications. In many countries, over half the population use =obile phones and the market is growing rapidly. At the end of 2009, there were =n estimated 4.6 billion subscriptions globally. In some parts of the =orld, mobile phones are the most reliable or the only phones available. Given the large number of mobile phone users, it is important to =nvestigate, understand and monitor any potential public health impact. Mobile phones communicate by transmitting radio waves through a =etwork of fixed antennas called base stations. Radiofrequency waves are =lectromagnetic fields, and unlike ionizing radiation such as X-rays or gamma rays, =annot break chemical bonds nor cause ionization in the human body. Exposure levels Mobile phones are low-powered radiofrequency transmitters, operating =t frequencies between 450 and 2700 MHz with peak powers in the range of =.1 to 2 watts. The handset only transmits power when it is turned on. The power =and hence the radiofrequency exposure to a user) falls off rapidly with =ncreasing distance from the handset. A person using a mobile phone 30–40 =m away from their body – for example when text messaging, accessing the =nternet, or using a “hands free” device – will therefore have a much =ower exposure to radiofrequency fields than someone holding the handset against their =ead. In addition to using "hands-free" devices, which keep mobile phones =way from the head and body during phone calls, exposure is also reduced by =imiting the number and length of calls. Using the phone in areas of good reception =lso decreases exposure as it allows the phone to transmit at reduced power. =he use of commercial devices for reducing radiofrequency field exposure has not =een shown to be effective. Mobile phones are often prohibited in hospitals and on airplanes, as =he radiofrequency signals may interfere with certain electro-medical =evices and navigation systems.
- 2. Are there any health effects? A large number of studies have been performed over the last two =ecades to assess whether mobile phones pose a potential health risk. To date, no =dverse health effects have been established for mobile phone use. Short-term effects Tissue heating is the principal mechanism of interaction between radiofrequency energy and the human body. At the frequencies used by =obile phones, most of the energy is absorbed by the skin and other superficial =tissues, resulting in negligible temperature rise in the brain or any =ther organs of the body. A number of studies have investigated the effects of radiofrequency =ields on brain electrical activity, cognitive function, sleep, heart rate and =lood pressure in volunteers. To date, research does not suggest any =onsistent evidence of adverse health effects from exposure to radiofrequency =ields at levels below those that cause tissue heating. Further, research has not =een able to provide support for a causal relationship between exposure to electromagnetic fields and self-reported symptoms, or =E2??electromagnetic hypersensitivity”. In contrast, research has clearly shown an increased risk of road =raffic injuries when drivers use mobile phones (either handheld or =hands-free") while driving. In several countries, motorists are prohibited or strongly =iscouraged from using mobile phones while driving. Long-term effects Epidemiological research examining potential long-term risks from radiofrequency exposure has mostly looked for an association between =rain tumours and mobile phone use. However, because many cancers are not =etectable until many years after the interactions that led to the tumour, and =ince mobile phones were not widely used until the early 1990s, epidemiological =tudies at present can only assess those cancers that become evident within shorter =ime periods. However, results of animal studies consistently show no =ncreased cancer risk for long-term exposure to radiofrequency fields. Several large multinational epidemiological studies have been =ompleted or are ongoing, including case-control studies and prospective cohort =tudies examining a number of health endpoints in adults. To date, results of epidemiological studies provide no consistent evidence of a causal =elationship between radiofrequency exposure and any adverse health effect. Yet, =hese studies have too many limitations to completely rule out an association. =/P> A retrospective case-control study on adults, INTERPHONE, coordinated =y the International Agency for Research on Cancer (IARC), was designed to =etermine whether there are links between use of mobile phones and head and neck =ancers in adults. The international pooled analysis of data gathered from 13 participating countries found no increased risk of glioma or meningioma =ith mobile phone use of more than 10 years. There are some indications of an =increased risk of glioma for those who reported the highest 10% of =umulative hours of cell phone use, although there was no consistent trend of =ncreasing risk with greater duration of use. Researchers concluded that biases and =rrors limit the strength of these conclusions and prevent a causal =nterpretation.
- 3. While an increased risk of brain tumors is not established from =NTERPHONE data, the increasing use of mobile phones and the lack of data for =obile phone use over time periods longer than 15 years warrant further research of =obile phone use and brain cancer risk. In particular, with the recent =opularity of mobile phone use among younger people, and therefore a potentially =onger lifetime of exposure, WHO has promoted further research on this group. =everal studies investigating potential health effects in children and =dolescents are underway. Exposure limit guidelines Radiofrequency exposure limits for mobile phone users are given in =erms of Specific Absorption Rate (SAR) – the rate of radiofrequency =nergy absorption per unit mass of the body. Currently, two international bodies 1 2 have developed exposure guidelines for workers and for the general =ublic, except patients undergoing medical diagnosis or treatment. These =uidelines are based on a detailed assessment of the available scientific evidence. =/P> WHO'S response In response to public and governmental concern, WHO established the International Electromagnetic Fields (EMF) Project in 1996 to assess the =scientific evidence of possible adverse health effects from =lectromagnetic fields. WHO will conduct a formal health risk assessment of =adiofrequency fields exposure by 2012. Meanwhile, the International Agency for =esearch on Cancer (IARC), a WHO specialized agency, is expected to review the =arcinogenic potential of mobile phones in 2011. WHO also identifies and promotes research priorities for =adiofrequency fields and health to fill gaps in knowledge through its Research =gendas. WHO develops public information materials and promotes dialogue among =scientists, governments, industry and the public to raise the level of understanding about potential adverse health risks of mobile phones. 1 International Commission on Non-Ionizing Radiation =rotection – ICNIRP. Statement on the "Guidelines for limiting exposure to =ime-varying electric, magnetic and electromagetic fields (up to 300 GHz)", 2009. =/P> 2 Institute of Electrical and Electronics Engineers IEEE =td C95.1 – 2005. IEEE standard for safety levels with respect to human =xposure to radio frequency electromagnetic fields, 3 kHz to 300 GHz. For more information contact: WHO Media centre Telephone: +41 22 791 =222 E-mail: mediainquiries@who.int © WHO 2010