Monday, 20 May 2019

Long-term mobile use not linked to ear nerve tumours, say Swedish researchers

WorriedLong-term mobile phone use does not increase the risk of ear nerve tumours, but it might increase the chances of you noticing you have it, Swedish researchers have found.

A study of long term mobile phone use and acoustic neuroma – a rare benign tumour of the ear nerve –  has found not only was there no increased risk but that the hearing loss caused by the disease may have caused previous findings of a link with mobile phone use.
“The findings do not support the hypothesis that long-term mobile phone use increases the risk of acoustic neuroma. The study suggests that phone use might increase the likelihood that an acoustic neuroma case is detected and that there could be bias in the laterality [side of the head] analyses performed in previous studies,” the researchers concluded in the paper published in the scientific journal Epidemiology.
Because of concerns that the radio waves from mobile phones held right next to the ear might cause acoustic neuromas, researchers from the Karolinska Institute in Stockholm conducted a nation-wide, case-control study of 451 patients with acoustic neuroma which covered a period in which mobile phones had been available for 20 years in Sweden.
The researchers asked about their mobile phone use including when they first started using a mobile phone and how many calls they made per day and if they used a hands-free device. 
The researchers found regular mobile phone use – defined as weekly use for at least 6 months – was not associated with a significantly increased risk of acoustic neuroma.
Because the diagnosis of acoustic neuroma is often associated with tinnitus or progressive hearing loss it is possible the onset of the tumour is more likely to be noticed on the side of the head that a person typically uses their phone,
The researchers also found that most of the tumour patients had changed the side of the head that they used their phone at least two years before their tumour was diagnosed whereas non tumour patients rarely changed their preferred side.
“As unilateral hearing loss is a common early symptom of acoustic neuroma, cases may have had to change their preferred side of mobile phone use long before the tumour was diagnosed,” the researchers said.
The researchers also raised the possibility that this pattern may have also impacted on previous studies which found a possible link with the disease.
“Another potential explanation for the unexpected pattern is that phone use may increase the probability of tumour detection by drawing attention to the unilateral hearing loss that is commonly caused by the disease,” the researchers said.
“Such an effect would bias the risk estimates upward and mainly be present for the smallest and least symptomatic tumours, whereas people with more severe disease would have had their tumour detected anyway, and detection bias would be less likely.”


Published 9/04/2014

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