MOBILE PHONE & BRAIN TUMOUR
Ankit Kumar Jhangta,
Kumaun Univ. Nainital
Mobile telecommunication technology became commercially available about 20-30 year ago in different countries around the world commencing with europian countries. Telecommunication Industry has grown by leaps and bound over the last decade. Thus any health hazard from these devices promises to have large epidemiological impact as more than half of the population are mobile users.The key aim of this paper is to scientifically and objectively review data suggesting or refuting a relationship between mobile phone usage and brain tumours.
Cellphone network were first deployed in Sweden in 1981 via the Nordic Mobile Telephone system in (analog;450MHz) First generation or “1G”.The digital system (GSM,Global System for Mobile Telecommunication)started in 1991(Second Generation or “2G”,900-1800MHz).The latest system currently in mass deployment is based on adaptations of CDMA and TDMA (800 and 1900MHz;3G)-REF.1
At present,there are about 3.8 billion people using mobile phone across the world,accounting for more than half of world’s total population-REF.2
With such high usage in the general population and with the beginning in childhood,we can expect a large number of people to be exposed to electromagnetic radiation for a prolonged duration which could have adverse effects on human health(infertility and cancer).This review attempts to present a comprehensive study of relationship between mobile phone usage and brain tumour.
BASIC PHYSICS PERTAINING TO MOBILE TELECOMMUNICATION SYSTEM
Mobile phone handset are devices that transmit and receive radio frequency waves(RF) which are transmitted bidirectionally between the handset and base station located terrestrially REF-3.
The most commonly used wireless protocol is GSM. Mobile phone can further be of two types-Analog and Digital.Analog phones transmit at much higher power than do digital phones.All mobile phones generate electromagnetic field.
An EMF is composed of an electric field generated by differences in voltage and a magnetic field generated by flow of current.REF-4
Human tissues absorb these radiations to different extent depending upon their frequency(or wavelength) which is inversely propotional to frequency.This absorption is expressed in term of specific absorption rate (SAR).
SAR is a measure of radiation absorption per unit weight of tissue and is expressed in unit of Watts/Kg.The radiation absorption of human body is maximum at frequency between 30-300 MHz.The international commission on non ionising radiation protection(ICNIRP) has laid regulation to control whole body SAR below 2W/Kg(averaged over 10 grams of tissue) for users of mobile phone.
RELATION BETWEEN MOBILE PHONE USAGE AND BRAIN TUMOUR
Incidence of brain tumour in mobile phone users has been extensively studied all over the world and research is still going on.Three types of intracranial tumours are considered in this review :-Glioma,Acoustic neuroma and Meningioma.Out of these Glioma is a malignant tumour with high case fatality rate. Acoustic neuroma and meningioma are benign and can be usually treated with early diagnosis.REF-5
Researches have mostly been case control studies using patient reported duration, intensity of usage and ipsilateral mobile phone use to the association with brain tumour. Incubation time or “Latency” (the time from the commencement of regular mobile phone usage to the diagnosis of malignant solid brain tumour in a susceptible individual).
Latency is usually very high ranging from 10-20 years. Cell phone use on the same side as tumour is Ipsilateral mobile phone use.
HOW MOBILE PHONE USAGE CAUSES BRAIN TUMOUR ?
The potential effect of mobile phone associated electromagnetic radiation on tissue include thermal and non-thermal effect.
Thermal effect are due to tissue being heated by radiation.The head/ear surface close to phone may be induced to heat.This heating has been thought to cause molecule within cell called Heat Shock Protein to become activated and repeated activation of such protein by microwave/electromagnetic wave can lead to cellular events culminating in cancerous transformation of cell.
Non-Thermal effects due to long term low level exposure to high frequency EMF may result in number of symptoms-headache,Fatigue,Sleep disorder and Memory impairment.REF-6
On the basis of various articles reviewed, there is insufficient evidence to indicate a casual association.
*The evidence is most suggestive for Ipsilateral tumours occuring with 10 or more years of use.REF-7 Previous negative studies may have failed to detect an effect due to an insufficient duration of exposure or Latency period.
Type of phone(analogue/digital) may influence this association.Analogue phones emit greater radiation and may be associated with an increased risk of tumour development than newer digital phones.Individual studies have examined the odds of using analogue phones but collectively no increased risk has been observed.REF-8
*On the basis of studies considering Ipsilateral use and more than 10 year of usage indicate increased risk and was significantly associated for Glioma and Acoustic neuroma but not for Meningioma.REF-9
*Existing research is limited to adults,little is known about potential risk to children.A large cohort study is underway to examine potential risk in this population group.REF-10
There is insufficient evidence to indicate a casual association between cell phone use and brain tumours.there is weak evidence supporting an increase in odds of Glioma,Acoustic neuroma and Meningioma in adults with regular Ipsilateral use for 10 years or longer.Existing findings are suggestive but preliminary because they are based on few studies with small number and potential biasis.
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4.National Collaborating Centre for Environmental Health,Canada.Cellular/Mobile phone use and Intracranial tumours September 2008
5. C Jolly & R.I. Marimoto “Role of Heat Shock response and Molecular chaperons in Oncogenesis and Cell death” Journal of National Cancer Institute(2000) volume 92 page 1564-1761
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9. Hardell L,Carlberg M,Soderqvist F,Mild KH.Meta-analysis of Long Term Mobile Phone use and the association with Brain Tumours.Int J Oncol 2008
10. Feychting M. CEFALO-A case control study of Brain Tumour in children and adolescent and Mobile Phone use.
Reference ID: PHARMATUTOR-ART-1003