MEDICAL MATTERS:Research confirms safety fears are warranted, writes MUIRIS HOUSTON
ARE MOBILE phones a danger to human health? With over five billion users worldwide, it’s certainly an important question. But it has proven immensely difficult to pin down a definitive answer.
Which makes last week’s announcement by the International Agency for Research on Cancer (IARC) especially noteworthy. It represents months of work by a panel of experts. They reviewed hundreds of scientific articles with the result the agency has now classified mobile phone signals as “possibly carcinogenic to humans”.
It means that radiofrequency electromagnetic fields – the type emitted by mobiles – are now in the 2b category of risk. While 2a means that an agent is probably carcinogenic to humans, IARC defines those in 2b as those for “which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals.”
The review group found limited evidence of a link between mobile use and the occurrence of glioma, a rare but potentially fatal form of brain cancer. It also flagged a possible link with acoustic neuroma, a benign tumour of the nerve that conducts hearing signals. And while the group did not quantify the risk, one previous study has found a 40 per cent increased risk for glioma among heavy users of mobile devices.
Chairman of the working group, Dr Jonathan Samet of the University of Southern California, said: “The conclusion means there could be some risk and therefore we need to keep a close watch for a link between cell phones and cancer risk.”
The IARC review included data from the Interphone study, which included participants from 13 countries. It concluded there was no increased risk of glioma associated with the use of mobile phones, although it did qualify this by noting there were “suggestions of an increased risk of glioma at the highest exposure levels”.
However, there is no data showing a greater incidence of brain cancer as the use of mobile phones has surged. A study by University of Manchester scientists found no statistically significant change in the number of brain tumours diagnosed in England between 1998 and 2007.
Meanwhile, new concerns about mobiles continue to emerge. Results of a recent Canadian study suggest the electromagnetic waves emitted by mobile phones can lead to low sperm quality – in count and mobility – and may result in decreased fertility in men. Critics have said the mobile phone industry needs to carry out safety tests that reflect where men commonly keep their phones, such as in trouser pockets.
And Turkish doctors last week reported that phones used by hospital patients and their visitors were twice as likely to contain potentially harmful bacteria as those belonging to healthcare workers.
The researchers, who published their findings in the American Journal of Infection Control, took swabs from the keypad, ear piece and microphone of each mobile device.
Some 40 per cent of the patient/visitor phones tested positive compared with 20 per cent of those belonging to healthcare professionals. And seven of the 200 phones tested had traces of drug-resistant bugs such as MRSA – all of which belonged to patients.
MRSA prevention has largely focused on hand hygiene practices by doctors and nurses. And while there may be little surprise at the organisms found on mobiles used by hospital staff, the findings for patients and visitors are unexpected. However, further research is needed to assess whether the contaminated phones are actually causing healthcare associated infections.
Finally here are some tips for safer mobile use:
Use a wireless head set: moving your head some 20cm from your phone significantly reduces the dose of radiation.
Try not to talk on your mobile for more than 30 minutes a day.
Minimise children’s use of mobiles and advise them to keep all calls short.