Wednesday, June 15, 2011

Relax, your cellphone won't kill you, experts say

There is no evidence that mobile phones are any more carcinogenic than coffee or pickled vegetables and Australians should be cautious of any mobile phone "gimmicks" promising to reduce radiation exposure, Australian health and bioengineering experts say.

One professor even rounded on top Sydney neurosurgeon Charles Teo for linking mobile phone use with cancer, arguing his view is out of step with mainstream science.

Earlier this month the World Health Organisation (WHO) sparked global alarm after declaring that it was "possible" mobile phones could cause cancer.

But question marks have been raised about whether any reduction in radiation is even necessary, as on the WHO's list of things that could cause cancer, mobile phones sit in the same category as 266 other common products including coffee and pickled vegetables.

Australian experts generally agree that the non-ionising radiation given off by mobile phones is too weak to damage human health.

But University of Wollongong Professor Rodney Croft, executive director of the Australian Centre for Radio Frequency Bioeffects Research (ACRBR), warned people to be cautious about "a number of gimmicks" purporting to reduce mobile phone radiation risks.

He said the WHO's International Agency for Research on Cancer (IARC) did not say that there was a link between mobile use and cancer but rather that they were unable to rule it out because of insufficient data at present.

"Many studies have shown that there is no measurable effect. This is obvious, of course, because there are millions of people using cell phones and if there had been any cancer inducing effect it would have been obvious by now."

Coster said studies had not been able to devise a link between low dose electromagnetic waves and cancer. "So far the only real effect [on human tissue] that has been noted is from intense RF [radio frequency] fields used in MRI machines that can cause light flashes [phosgenes] but even that is rare and requires very strong RF fields." he said.

Coster said that even if users were to completely shield themselves from the electromagnetic signals emitted by phones they would not be able to make calls.

The views about mobile phones and cancer differ markedly from those expressed by Teo, founder of the Centre for Minimally Invasive Neurosurgery at Prince of Wales Hospital in Sydney.

"There is an increasing body of evidence that there is an association between brain tumours and mobile phones," said Teo, adding the WHO report should be a "wake up call" alerting people to the links between mobiles and cancer.

But Croft said Teo's views "do not appear to be consistent with the current state of science".

The largest and longest study of mobile phone use, dubbed Interphone, covered 13 countries and found no overall link between mobile phone use and brain tumours. However, the study, published last year in the International Journal of Epidemiology, also reported that study participants with the highest level of mobile use also had a 40 per cent higher risk for glioma, an aggressive brain tumour.

A separate Israeli study published in The American Journal of Epidemiology found heavy mobile users had a 58 per cent higher risk of parotid gland tumours. The parotid gland is a salivary gland near the ear.

And Swedish research that analysed 16 studies on mobile phone use found a doubling of risk for acoustic neuroma (a tumour that occurs where the ear meets the brain) and glioma after 10 years of heavy mobile phone use.

However, all these studies are observational and show only an association between mobile phone use and cancer rather than a causal relationship. The overall rate of brain cancers worldwide has not changed in the time mobile phone use has become ubiquitous.

No studies have been conducted into the health effects of Bluetooth earpieces, but medical professionals have warned that they could actually expose users to more radiation than a mobile phone as the emissions go directly inside the ear.

Some have called for new rules forcing manufacturers to label their mobiles according to their emissions - or the SAR value - but Anderson said this was unnecessary because mobiles were already tightly regulated for safe exposure.

In Australia the Australian Communications and Media Authority (ACMA) already stipulates that the SAR limit for mobile phones is 2W/kg. The iPhone 4, for example, has a SAR rating of 1.17 W/kg.

"The SAR limits are very conservatively designed to protect against any potential adverse heating effects," Anderson said. "The equivalent 'SAR heating' of placing your hand against your face would be far more than the power absorbed by the RF EMF exposure of a mobile phone."


Woman's sleep side may affect chance of having stillborn baby

Some strange findings here but the effects are tiny in absolute magnitude so may be due to random factors

WHICH way a woman sleeps late in her pregnancy could affect her chances of having a stillborn baby, new research has revealed. The study found women who slept on their right side, or on their back, the night before they gave birth had double the risk of a stillbirth compared to those who slept on their left side.

The New Zealand research has raised the question of whether women should be advised to sleep on their left side late in their pregnancies.

University of Auckland PhD student by Tomasina Stacey, also found that women who get up to go to the toilet once or not at all on the last night of their pregnancy are more likely to have a stillborn baby.

Those women who regularly sleep during the day in the last month of pregnancy are also more likely to suffer a stillbirth, the investigation found.

And those who slept longer than average at night also increased their risk of stillbirth. However no link was found between snoring or daytime sleepiness and risk of late stillbirth.

Despite improved obstetric and neonatal care, the rate of stillbirth has been largely unchanged for more than 10 years in Australia. Australia is ranked 15th in the world for the rate of stillbirths, with seven in every 1000 Australian births results in stillbirth.

The New Zealand study, which appears in the British Medical Journal today, involved interviewing 155 women in Auckland who gave birth to a stillborn baby and who were compared to a control group of 310 women. Their age, smoking status, body mass index and social deprivation level were also taken into account.

Ms Stacey and her research team stressed that the increased risk of sleeping on the right side or on the back, compared to sleeping on the left side, was small, and more research was needed.

The "absolute risk'' of late stillbirth for women who went to sleep on their right side or back was 3.93 stillbirths per 1000 births, while for those who slept on their left side it was 1.96 stillbirths per 1000 births.


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