R E V I E W A R T I C L E
JIACM 2010; 11(3): 212-9Mobile Phone and Health Hazards
SH Talib*, Pritam Patil**, Prasad Nikam***
Abstract
With the advent of mobile telephones since 1956, there are about 1.6 billion users worldwide. Today there is an upsurge in the public and media concern about the possible hazards of this new technology, and specifically of radiofrequency field exposure1.
Furthermore, studies of mobile phone risks have received widespread public attention; their interpretation is not straightforward because of methodologic difficulties. In order to summarise the current state of knowledge, the epidemiological aspects about the effect of mobile phone on human health have been reviewed and discussed.
Key words: Mobile telephone, radiofrequency exposure, health hazards.
Introduction
In 2008, India had 287 million mobile phone users and nearly 1,15,000 towers which emit electromagnetic radiations. By the end of 2010, the number of mobile phone users is estimated to rise to 500 million2,3.
Mobile phones are low power radio devices that transmit and receive radio frequency radiation in the microwave range of 900 - 1,800 MHz through an antenna used close to the user’s head. Various types of analogue and digital cellular phones are in use across the globe. Analogue telephones transmit modulations of the amplitude or frequency of electromagnetic waves which are transmitted continuously. On the other hand, the digital telephones transmit data in series of pulses or fast bursts. The advantage of the digital systems is that they allow simultaneous transmission of messages of different users on the same frequency which increases the capacity of the transmission channels. Digital systems have recently replaced analogue.
There is concern that microwaves might induce or promote cancer, and the symptoms associated with their use include sleep disturbance, memory problems, headaches, nausea, and dizziness4. Changes in the permeability of the blood brain barrier, electroencephalographic activity, and blood pressure have also been reported5. The validity of many of these findings is uncertain, as are the mechanisms for such action.
How the mobile phone acts?
As shown in Fig. 1, when a call is made, voice (sound energy) is converted to radiofrequency waves (electromagnetic energy). Radio waves travel through the atmosphere to the nearest base station. At the call receiver’s end, waves travel from the base station to the receiver’s wireless phone. The receiving instrument re-converts radiofrequency wave to sound energy and the receiver hears this as voice in the ear piece.
In mobile phone technology, there are two main transmission protocols. The Global System for Mobile Communication (GSM) was established in 1987 and is the dominant protocol used in India and most European countries. Another protocol, founded by Qualcomm (a USA-based mobile service provider), is the Code Division Multiple Access (CDMA) standard. In India, GSM phones use transmission frequencies of 890 915 MHz or 1710 1785 MHz for uplink (handset to base station) and 935 -960 MHz or 1805 - 1880 MHz for downlink (base station Fig. 1: Showing the down and uplinking of telephone action. (Source: http://gsmfordummies.com/intro/images/ gsm900_arfcn1.jpg).
to handset). The CDMA phones use frequencies of 824 -849 MHz for uplink and 869 - 889 MHz for downlink.
The majority of health hazards by the mobile phone are due to exposure to electromagnetic radiation.
Electromagnetic radiation and concept of
SAR
Electromagnetic radiation has been around since the birth of the universe; light is its most familiar form. Electric and magnetic fields are part of the spectrum of electromagnetic radiation which extends from static electric and magnetic fields, through radiofrequency and infrared radiation, to X-rays. Electromagnetic fields are present everywhere in our environment but are invisible to the human eye. Electric fields are produced by the local build-up of electric charges in the atmosphere associated with thunderstorms.
The electromagnetic spectrum also includes fields generated by human-made sources like X-rays and the electricity associated low frequency electromagnetic
fields. Various kinds of higher frequency radio waves are used to transmit information – via TV antennas, radio stations or mobile phone base stations. Various electromagnetic spectrum and radiofrequencies of various rays are shown in Fig. 2.
Electomagnetic waves can be divided in ionizing and non-ionizing radiations. X-ray, gamma rays are the examples of ionizing radiation. They are particularly hazardous to health and have tumourogenic potential. Mobile phone radiations are non-ionizing and thus typically safe.
International bodies such as the National Radiological Protection Board (NRPB) has set the standards for recommended radiation limits which are measured in ‘specific absorption rates’. The NRPB says the vast majority of studies have shown radiation levels from cell-phones are too low to harm humans, and recommends a limit of 10 milliwatts per gram3.
Specific Absorption Rate (SAR) is a unit of measurement for the amount of Radio Frequency or ‘RF’ energy absorbed by the body when using a mobile phone. SAR is also the
Fig. 2: Showing electromagnetic spectrum and radiomagnetic frequencies of various rays. (Source: http://www.arpansa.gov.au/images/ mobilephones/spectrum.gif ).
The Electromagnetic Spectrum Mobile Phone System AM Radio FM Radio and Television Long Radio waves 10 10 Wave length (mm) 7.6 x 10-5 4.0 x 10-5 Visible light 8 6 4 2 0 -2 -4 -6 -8 -10 -12 10 10 10 10 10 10 10 10 10 10 10 Radio waves MC RO waves Infra-Red
rate at which the RF energies are absorbed by a given mass of material, as evidenced by a rise in material temperature.
What are electromagnetic hazards?
The electromagnetic hazards by mobile phone can be divided into two parts:
1. Thermal health hazards 2. Non-thermal health hazards
1. Thermal health hazards of mobile phone
Thermal effect is one whereby the electromagnetic field of radio waves induces polar molecules that generates dielectric heat letting the live tissues die. For instance some part of head, while receiving the message through radio waves may experience increased temperature and may result in damage to nerve fibres.
Mobile phone and cataract
Mobile has been linked with development of cataract as cornea lacks the thermoregulatory mechanism. The formation of lens opacities in the eyes of laboratory animals following acute microwave exposure is well established. It is generally accepted that acute exposure to higher levels of radiation causes various degrees of lens opacification in laboratory animals at many microwave frequencies. However, the exact conditions under which these changes may occur in human beings are a subject of debate6.
2. Non-thermal health hazards
Possible non-thermal effects of mobile phone are related to genotoxic effect, i.e., brain cancers, and interference with cardiac pacemakers.
Genotoxic effect
It is known that ionizing radiations like gamma rays, X rays cause DNA break-up and mutation. The same theory has been postulated, i.e., whether mobile phone radiations which are non-ionizing radiations can cause a similar effect on the human genome. To test this hypothesis the REFLEX (Risk Evaluation of potential environmental hazards From Low Energy magnetic field) study was conducted by the European union7. The study
working from 2000 to 2004. In the course of this study, the so-called mutagenicity by electromagnetic fields was tested in vitro. Several of the teams detected significant DNA breaks in human and other animal cells at the exposure levels which was far below the official limits. In the RF region, the DNA breakages as well chromosomal abnormalities were observed at the lowest SAR level investigated, i.e., 0.3 W/kg.
The final report states that: “Taken together, the results of the REFLEX project were exclusively obtained in vitro
studies and are, therefore, not suitable for the conclusion that RF-EMF exposure below the presently valid safety limits causes a risk to the health of people7.
In vitro experiments on cell proliferation, membrane properties, and ion channels are difficult to extrapolate to humans. Moreover, it is also difficult to extrapolate effects on brain function and behaviour from rodents to humans because the entire brain of a rat or mouse is exposed but for a person using a mobile phone only the small region of the head that is close to the phone would be exposed. Although some studies have claimed to show an increase in DNA strand breaks in rats, others have failed to replicate this finding8.
Mobile phone and cancer
The initial case-control studies of brain tumours and mobile phone use were conducted in Sweden during 1994 - 19969-11. In these studies, details were taken about the intensity and duration of mobile phone use, preferred side (ear) of use, phone type (analogue or digital), and hand-held or hands-free.
A similar second larger study a few years later by the same authors was carried-out12. It involved 1,303 cases (half of all brain tumours diagnosed 1997 - 2000) along with controls. Ipsilateral use of analogue phones was related to temporal tumours [OR = 2.5 (95% CI, 1.3 - 4.9)], and analogue phone use was associated with acoustic neuroma [OR = 3.5 (95% CI, 1.8 - 6.8)]12,13.
Muscat et al in 2000 conducted two hospital-based case-control studies in the United States, one of malignant brain tumours, the other of acoustic neuromas14,15. In the first study, no increased risks were seen relating to frequency, duration of mobile use for site, or histological subtype of
brain cancer. In the second study, an increased risk of acoustic neuroma was found on the same side of mobile phone use among 41 cases15.
In another US hospital-based case-control study16, interview data were obtained from 782 cases with brain tumours and 799 matched hospital controls with nonmalignant conditions. Results showed no association between cumulative use of mobile phones (mainly analogue) and brain tumours.
In a Finnish case-control study17, 398 diagnosed cases of brain tumours were studied retrospectively with matched controls. The OR (odds ratio) for brain tumours was 2.1 (95% CI, 1.3 - 3.4) for analogue phones and 1.0 for digital, and the OR for glioma was 1.5 (95% CI, 1.0 - 2.4) for any phone subscription.
In another two cohort studies, one is US based with 28,561 mobile phone users. The study reveals no relationship between mortality from brain cancer and the use of hand-held versus hands-free phones. The second cohort study was in Denmark and included 420,095 mobile phone users. Comparing cancer rates in phone users showed no relation to the risk of brain and nervous system cancers18,19. Further, no association was seen with parotid gland tumours in the Finnish case-control study17 and also in the Danish cohort study19.
An expression of exposure to mobile phones for several hours a day for ≥ 6 months was studied in relationship of uveal melanoma. The study revealed no increased risk of uveal melanoma due to mobile phone exposure20.
In the recent work by Christensen et al (2004)21, no relation between acoustic neuroma and mobile phone use was found.
Mobile phones and implantable rhythm
device (IRD)
IRD is the generic name for the group of implantable devices used for treatment of cardiac arrhythmias, e.g., cardiac pacemakers and implantable cardioverter defibrillators. Since these devices have complex microelectronic circuitry and use electromagnetic waves for communication with programmers, they became susceptible to interference from most sources of
electromagnetic radiation and magnetic energy22.
Cellular telephones use radio frequency waves for communication and are likely to interfere with the function of implantable rhythm devices. Cellular telephones produce both static and dynamic electromagnetic fields. The magnet in the ear piece of the phone produces a low energy static magnetic field. This static magnetic field can activate the internal reed switch causing temporary suspension of sensing function when placed in close proximity to the implanted device23. Dynamic fields with much higher intensity are produced by the radio frequency energy used for communication. Today we have two basically different communication systems, analogue and digital systems that vary in their ability to produce interference with IRDs.
Digital phones are more likely to interfere with IRDs than analogue phones. This is because the pulse repetition rate of the devices falls within the frequency range of physiological signals. The earliest series in this review was by Barbaro et al (1995)24. This study involved 101 patients with 43 pacemaker models from 11 manufacturers. 26 patients showed interference at minimum sensing thresholds, with the phone in direct contact with the patient’s chest. Pulse inhibition (9.9%), ventricular triggering (19.5%) and asynchronous pacing (7.7%) were the common interferences noted. Maximum distance at which interference occurred was 10 cm with the pacemaker programmed at its minimum sensing threshold.
The study by Hayes et al (1997)25 involving 980 patients with implanted pacemakers was a designed study with five types of cellular phones (one analogue and four digital). The telephones were programmed to transmit full power, to mimic the worst case situation. Of a total of 5,533 tests conducted, interference was noted in 20%, of which 7.2% were symptomatic. Clinically significant interference was seen in 6.6%. No significant interference was noted when the telephone was placed in the standard phone position over the ear. As expected, interference was much higher when the phone was placed near the pacemaker. Marked difference was noted in the incidence of EMI between analogue and digital phones (2.5% vs 23.7%, P = 0.01).
In the study by Altamura et al (1997)26 which included 200 patients, interference was much more common during ringing than on/off phase (131 vs 26 episodes, P < 0.0001). Incidence of interference increased with increasing sensitivity (106 at maximum sensitivity vs 51 at basal values; P < 0.0001). The authors concluded that if phones were not carried close to the pacemaker, safety was not compromised.
Raden et al (1999)27 reported a study on 144 patients with implanted pacemakers (134 with single chamber and 10 with dual chamber). The tests were conducted with the phone directly over the pacemaker site. While 9 patients (6.25%) had intermittent pacemaker inhibition at basal settings, 17 patients (11.8%) showed inhibition on reprogramming to maximum sensitivity.
Hofgartner et al (1996)28 reported on 104 patients with 58 different models of pacemakers. Interference was noted in 28 different pacemaker types (48.3%) spread over 43 patients (41.3%). Pacemaker inhibition, noise reversion, and triggering of pacemaker mediated tachycardia were noted.
The largest report of the current decade from Tandogan
et al (2005)29 included 679 patients. Interference was noted in 37 patients (5.5%). Thirty-three pacemakers were converted to asynchronous mode and 3 were inhibited. One pacemaker developed ventricular triggering. Interference was more common when the lead polarity was unipolar (4.12% vs 1.40%, p < 0.01). These interferences did not cause any symptoms and the pacemaker function returned to normal when the cell phone was removed away from the patient.
Interference with implantable cardioverter
defibrillators
The largest available study was on 97 devices reported by Niehaus et al in 200230. Interferences (loss of communication or temporary inactivation of the device during interrogation) were noticed in 38 patients. Most of these (93%) occurred while testing close to the device. Jimenez et al31 published in 1998 their study on 72 patients of which 14 showed interference. But none of these were clinically significant.
ICDs from five different manufacturers. This study was unique in that it reported interference with all the evaluated models. The interference consisted of noise in telemetric transmission when the phone was located near the ICD and the programmer´s head. The noise was most significant during call and reception, leading to loss of telemetry in most cases. It is important to note that there was no false arrhythmia detection during the tests, neither a delay in recognition of induced ventricular fibrillation. Hence they suggested that patients with implanted ICDs may use cellular phones, but not during ICD programming and interrogation.
In contrast to the above report, Fetter et al33 who studied the effect of digital phones on ICDs, reported no interference due to over-sensing of the dynamic electromagnetic field in their 41 patients. However, they found that the static magnetic field of the phone’s earpiece placed over the ICD will activate the internal reed switch causing temporary suspension of ventricular tachycardia and fibrillation detection.
From the above studies it can be concluded that cellular phones are likely to interfere with implantable rhythm devices if operated in close proximity or during programming of the device. Patients with implanted devices can safely use cellular phones if they are not carried close to the implanted devices or operated near them. Carrying the cellular phones in the belt position, receiving calls in the ear opposite to the side of the implanted device and keeping the phone as far away as possible while dialling can be considered a safe practice.
Mobile phone and infertility
The frequency of cell phone radiation ranges between 850 and 1900 MHz. As energy carried by cell phone radiation [radiofrequency electromagnetic waves (RF-EMW)] is extremely low compared to ionizing radiation, i.e., X-rays (frequency, 1010 - 1018 MHz), they do not cause ionisation of molecules. However, exposure to RF-EMW causes a number of effects on biological systems. Results of various studies demonstrating effects of cell phone radiation on male fertility are conflicting due to heterogeneity of data and research methods34. Epidemiological studies have proposed cell phone usage
Recently, Agarwal et al in (2008) demonstrated effect of cell phone usage on semen analysis in men attending an infertility clinic. The most remarkable finding of this study was the significant association of cell phone usage with reduced sperm motility in men using cell phone > 4 h/day vs. men not using at all (p < 0.0001)35.
Baste et al (2008)37 studied infertility among military men employed in the Royal Norwegian Navy. They reported odds ratio (OR) of 1.86 among military personnel with exposure to RF-EMW relative to those who reported no work near RF-EM (electromagnetic) field.
fatigue, stress, sleep disturbances, skin symptoms like prickling, burning sensations and rashes, ache in muscles and many other health problems. Whatever its cause, EHS is a real and sometimes a disabling problem for the affected persons. “EMF Hypersensitivity” is a poorly defined condition. It is said to include various symptoms, such as fatigue, headaches, skin rashes and insomnia which occur in association with exposure to low levels of electromagnetic fields The syndrome involves the nervous system and includes fatigue, headaches, synaesthesia and various autonomic effects39, neurological (tingling, fatigue, headache), musculoskeletal, cardiovascular, and dermal symptoms40.
Table I: Showing list of top 10 lowest and highest radiation mobile phones in use worldwide.
Manufacturer and model* SAR level Manufacturer and Model SAR Level
1. Motorola StarTAC 7860 0.24 1. Ericsson T28 World 1.49
2. Qualcomm pdQ-1900 0.2634 2. Nokia Digital 5160 1.45
3. Mitsubishi Trium Galaxy G-130 0.35 3. Nokia 5170 1.45
4. Motorola TalkAbout 2297 0.35 4. Denso TP 2200 1.44
5a. Motorola ST7797 0.39 5. Qualcomm QCP-1960 1.41
5b. Motorola T8097 0.39 6. Sanyo SCP-4500 1.4
5c. Motorola P8097 0.39 7. Sony CMB-1200, 2200, 3200 1.3906
6. Motorola StarTAC 7790i 0.42 8. Nokia 8860 1.39
7. Motorola i1000plus 0.43 9a. Motorola StarTAC 7867 1.38
8a. Motorola G520 0.457 9b. Motorola ST7767D 1.38
8b. Motorola M3682 0.457 9c. Motorola Talkabout T8167 1.38
9a. Ericsson KF-688 0.477 9d. Motorola Timeport P8167 1.38
9b. Ericsson DF-688 0.477 10. Neopoint NP-1000 1.38
10. Motorola M3097 0.53
(Source: www.globalchange.com/radiation.htm).
Electromagnetic hypersensitive syndrome
In the past years, the percentage of the general population suffering from non-specific health symptoms, including sleep disturbance has grown. An increasing number of affected people associate their symptoms with the exposure to electromagnetic fields, ELF as well as RF, claiming themselves to be electromagnetic hypersensitive. Sensitivity to EMF has been given the general name “Electromagnetic Hypersensitivity” or EHS38. It comprises nervous system symptoms like headache,The term “Idiopathic Environmental Intolerance (IEI) with attribution to EMF” was proposed by the WHO working group in the International Workshop on EMF Hypersensitivity to replace EHS since the latter implies that a causal relationship has been established between the reported symptoms and EMF38.
What are the preventable measures
The Government of India’s Department of Telecommunications (DoT) adopted the guidelines set by
the International Commission on Non-Ionising Radiation Protection (ICNIRP) and released a set of draft guidelines.
The salient points from these guidelines are:
“It will now be mandatory for handset manufacturers to display the radiation levels on mobile phones through the menu options, making it easier for consumers to know the exact levels for each mobile device before purchase”.
Unfortunately, the Cellular Operators Association of India (COAI) has opposed the regulation demanding display of SAR values emitted by the handset. COAI also opposed a move from DoT to set up a conformity assessment body (CAB), which will measure radiation from mobile base stations and provide certifications to the operators2.
Following are the general safety guidelines for mobile phone use:
1. Children under 16 years should not use mobile phones.
2. Use mobile phones only in emergencies and that too only briefly.
3. A mobile phone in the trouser pocket and also the sending of SMS messages under the school desk can influence fertility and should be completely avoided. 4. If sending SMS messages, keep the mobile phone
away from the body.
5. Play no games on the mobile phone.
6. Keep the mobile phone away from the head during the telephone connection.
7. Keep the mobile phone a couple of metres distance away from other people as they too are being radiated along with you.
8. Less mobile phone telephone calls mean less radiation from mobile phone.
9. Internet via cable connections – UMTS and WLAN – lead to high radiation exposure.
10. Turn-off the mobile phone at night – if left turned on, do not keep it near the head.
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