The New Straits Times, January 22, 1998
Q: Recently, I came across reports that electromagnetic fields from mobile telephones could cause brain cancer. How true is this?
A: As an introduction, electromagnetic fields or EMFs generated from mobile cellular telephones are a result of electrical usage by the equipment.
These electrical fields are considered to be low energy fields which can emanate from anything electrical such as microwave ovens, personal computers, electric power stations and high-voltage power lines.
The EMFs travel through the air and can also pass through our bodies. Due to this ability to penetrate the human body, concerns of their effects to the human body were raised as early as the 1980s.
Safety awareness was further heightened due to numerous studies which related the effects of EMFs to certain cancers and other health problems. Such studies suggested that there might be an increased risk of leukaemia, lymphoma and cancer of the nervous system in children living near high-voltage power lines. In other studies, elevated risks of these diseases were reported in electricians and telephone line workers.
In addition, there were also studies which linked miscarriages and birth defects in pregnant women exposed to high levels of EMFs on the job. EMFs were also thought to contribute to the rising incidence of breast cancer. On a more extreme note, EMFs have been linked to depression and suicide.
The underlying physical and biological mechanisms reported to be associated from exposure of EMFs are at present being further tested at the cellular level. Some of the possibilities proposed thus far are:
EMFs alter the movement of calcium ions in cells. Calcium is one of the main messengers that shuttle vital information across cell membranes. It is also responsible for maintaining many processes including cell growth and division.
EMFs suppress the production of melatonin. Melatonin is a hormone which is produced in the brain and acts to regulate our biological clock. It may also play a major role as a tumour growth-inhibiting factor. A suppressed level of melatonin has been linked to different forms of cancer, particularly prostate and breast cancers. Scientists have found that exposure to EMFs can decrease night time production of melatonin and they believe that this reduction may allow cancerous cells to proliferate unchecked.
EMFs may stimulate growth and repair of both normal and cancerous cells. Low frequency radiation has been used as therapy to help broken bones heal faster, and some scientists believe that EMFs might likewise cause tumours to grow faster.
EMFs cause changes in the production of a number of hormones and neurotransmitters and, consequently changes in brain activity. This may lead to alterations of most of our body's functions.
EMFs may induce changes in the genetic material, ribonucleic acid (RNA), which is copied from deoxyribonucleic acid (DNA) and transmits genetic information that cells use to make proteins.
EMFs change the activity of immune cells.
EMFs slow down the heart.
It must be emphasised again that these subtle effects are observed from laboratory experiment and as such, do not necessarily reflect health problems in real life.
Based on these preliminary observations as well several epidemiological studies, the scientific community is still deeply divided over the issue of the safety of EMFs even though citizens of many developed countries have taken a rather aggressive stand on this issue.
One school of thought believes that the association between EMF exposure and cancer, no matter how small, is very real. Their adversaries argue that these studies have not been able to rule out other possible confounding exposure factors.
Using the same epidemiological studies carried out from the EMF study, a group of scientist found that the incidence of childhood cancer was unrelated to EMF exposure but could be associated with traffic density. The odds of this associations were greater than those reported earlier for EMFs and cancer.
One potential consequence of high traffic density is a high level of benzene, which is known to cause cancer, in particular, leukaemia. Among the criticisms was that the consistency of findings of the various epidemiological studies was indeed rough, in the sense that the description to exposure levels in these studies were clearly inconsistent.
Thus, it is thought that the variability and complicated nature of EMF characteristics would not allow researchers to even design definitive studies of EMF health effects.
To conclude, the safety aspect of exposure to EMFs, especially from mobile cellular telephones, warrants further evaluation based on well-documented studies. And until such data can be obtained, the best approach to adopt is to weigh the risk-benefit ratio from using such technologies. - National Poison Centre
