Cellphone questions unanswered
The long-awaited results of a US$25 million study on the effects of cellphone radio frequency radiation exposure on animals is out, and the results are mixed.
They showed a higher risk of tumours, DNA or tissue damage and lower body weight in some groups of rodents, but no obvious ill effects in others, and no clear implications for human health.
John Bucher, a senior scientist involved in the 10-year US National Institutes of Health study, was cautious in his interpretation of the results yesterday.
Given the inconsistent pattern of the findings, the fact that the subjects were rats and mice rather than people, and the high level of radiation used, he said he could not extrapolate from the data to potential health effects on humans.
‘‘At this point, we don’t feel that we understand enough about the results to place a huge degree of confidence in the findings,’’ he said.
Bucher also said that ‘‘I have not changed the way I use a cellphone’’.
The study by the National Toxicology Programme is believed to be the most comprehensive assessment of the health effects of such radiation on rats and mice, and involved 3000 test animals. A draft report was released yesterday for public comment and peer review, in advance of an external expert review in March.
The issue of cellphone radiation’s impact on human health has been hotly debated for years.
In 2010, the US Federal Communications Commission came under fire after it dropped a longstanding recommendation that consumers buy phones with lower radiation emissions.
In 2015, the city council in Berkeley, California approved an ordinance that directed cellphone sellers to let buyers know of the risk of carrying devices too close to their bodies. The CTIA, which represents the US wireless industry, has sued the council, saying the warnings are ‘‘ill-informed’’ and violate retailers’ First Amendment rights.
The strongest finding in the new study involved male rats – but not female rats or male or female mice – which developed tumours in the nerves surrounding their hearts. Researchers also saw increases in damage to heart tissue in both male and female rats.
If these results were confirmed, Bucher said, they appeared to suggest that this type of radiation could be a ‘‘weak’’ carcinogen.
The International Agency for Research on Cancer currently lists radio frequency fields as ‘‘possibly carcinogenic to humans’’.
The study showed tumours in rats and mice in other parts of the body – the brain, prostate, liver and pancreas – but the scientists said it was unclear if these were related to the radiation.
The experiment involved placing rats and mice into special chambers and exposing them to different levels of radiation that mimicked 2G and 3G phones for nine hours a day.
Bucher emphasised that even the lowest levels used in the study were much higher than the maximum exposure even a frequent cellphone user would get.
In addition to cancer, the study looked at other health effects such as evidence of tissue damage from the heat of cellphones, DNA damage, and changes in body weight.
It said there were some tissue and DNA issues but ‘‘we don’t feel sufficient understanding to comment on their biological significance’’.
For example, Bucher said, ‘‘the patterns of damage to brain in tissues in these animals are not particularly consistent with tumour outcomes’’.
Some health and environmental groups immediately seized on the findings as more evidence of the dangers of cellphones. The Environmental Working Group’s Olga Naidenko, a senior science adviser, said the study ‘‘should raise alarms for policymakers and awareness for all Americans’’.
The response from the US Food and Drug Administration, which commissioned the study, was more muted.
Jeffrey Shuren, director of the FDA’s Centre for Devices and Radiological Health, said his team was continuing to assess the results, but based on all available scientific information, the agency did not believe there were adverse health effects in humans caused by cellphone radiation.
‘‘Even with frequent daily use by the vast majority of adults, we have not seen an increase in events like brain tumours,’’ Shuren said.
Based on this current information, we believe the current safety limits for cellphones are acceptable for protecting the public health.’’
At this point, we don’t feel that we understand enough about the results to place a huge degree of confidence in the findings. John Bucher, senior scientist in National Institutes of Health study