A recent Cancer Research UK article looks into the evidence behind mobile phones, wi-fi and power lines. Ionising radiation is where there is enough energy to make changes to our cells, non ionising radiation has less energy, therefore is used in a wide range of communication and electronic devices. Microwaves, electomagnetic fields and radio frequencys use different types of non ionising radiation.
What is the evidence behind mobile phones?
There is not enough scientific evidence to completely rule our the risk, but so far what we do know is that it is unlikely that mobile phones could increas the risk of brain, or any other type of cancer. In 2011 the International Agency of Research (IRAC) for cancer classified mobiles in their ‘gold-standard’ rating system. They said that mobiles could ‘possibly’ cause cancer in humans but there wasnt enough evidence to derive a clear conclusion.
There have been may scientific studies trying to find a possible link, but many have been too small to be significant in proving either way.
The IARC decision in 2011 was based on the results of two studies, research conducted by Swedish Hardell and a large international study called InterPhone, although the IARC didn’t feel there was enough evidence to come to a decision.
The Hardell study suggested a connection between using a mobile phone and a few specific types of brain tumour, particularly in heavy users. InterPhone studied 6,000 people across 13 countries and largely found no link between mobiles and brain tumours. However in the ten percent of people who used their phones the most there was a link, but this can be explained by problems in the design of the study. Both studies have drawbacks as they are rleying on people remembering how much they use their phones in the past, answers may have been subconisouly affected by peoples personal thoughts on cancer and phone usage, and tumour themselves may affect peoples memory.
A Cohort study is a more reliable source as it asks people about their phone usage habits, then follows them up after a specific period of time to study any patterns in diseases. The largest study of this kind was part of the Million Women Study, which looked at about 790,000 women. There was no link found at all with brain, or 18 other types of cancer, and mobile phones. There was no increased risk for most types of brain tumour, including the two most common Glioma and Meningioma, however there was an incease in one rare type of tumour. This raised risk was seen for Acoustic Neuroma and occured in women who had used mobiles for at least five years, however after a further two years of study, this risk was no longer found, so no evidence of risk was found. A simial Danish cohort study of 420,000 people also found no link between any type of cance and the use of mobile phones.
A study by a Swedish group in 2014 unusually found that people who in fact use mobile phones are more likely to notice the symptoms of Acoustic Neuroma, such as hearing loss, which may lead to a quicker diagnosis. So the use of mobiles may help to increase the detection of the disease, this has lead to ongoing research of this evidence.
Cancer rates and mobiles
Since the 1980s the use of mobile phones has grown unbelievably, so most people would think that if using mobile phones caused cancer then number of cancer cases should have increased! However the rate of new brain tumour cases have hardly changed over the years. In the UK the rates have only slightly increased in the past few decades, but the change in number is just thought to the improvement in data collection in more recent years.
It is worth noting that brain tumour can take many years to develop so it may be possible that diagnosis rates would only increase many years after the boom in usage.
Is mobile phone radiation dangerous?
The radiofrequency electromagnetic radiation that mobile phones recieve and transmit are very weak, there is not enough energy to damage our DNA and cannot directly be the cause of cancer. In 2012 an independent report concluded that there was no convincing evidence that being radiofrequency exposure within the guidelines could affect somebody’s health. The UK follow international safety standards, which restricts the amount of electromagnetic radiation people can be exposed to and have a very large safety margin.
How do mobile phone masts and base stations figure?
It is unlikely that mobile phone masts and base stations would increase your risk of cancer, they were included in above review which found no convincing evidence that the radiation they gave off can affect health. The exposure you would get from a base station is usually at least a hundred times below the international guidelines, and consequently a lot less that the exposure from your mobile phone.
Wi-fi and Smart meters
There has been some speculation in the media about the use of wi-fi and smart energy meters in our homes and whether or not the radio waves cause cancer. There is no need to worry as the radio waves produced by these devices are much weaker than those of mobile phones, so there is not a health risk.
The radiation given off from power lines is different to that seen in mobile phones and home applicances. There is little evidence to show any link with adult cancers, although some studies have suggested a statistic link between childhood leukaemia and exposure to magnetic fields. There isnt enough evidence to confirm the link but it is thought that about 1% of childhood leukaemias may be due to this exposure.
Two studies have found that the very small number of children who were exposed to the highest magnetic fields had a higher risk than the children exposed to the lowest levels. As the studies they were based on had very variable results, they weren’t sure that power lines or magnetic fields caused the higher risk, especially as there is no reasonable explanation for how this might occur.
The IRAC, supported by the World Health Organisation, rated low frequency magnetic fields as a ‘possible’ cause of childhood leukaemia, meaning we cannot rule out the risk. At present there isn’t a convincing suggestion for how magnetic fields may cause leukaemia, but combining several studies together then there does seem to be a raised risk. However if there is a link then the impact would be small as only around 1 – 4% of children have the highest levels of exposure.