Lengthy study leaves cellphone questions unanswered
WASHINGTON 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.
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 123RF.COM 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 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. The lowest levels used in the study were much higher than the maximum exposure even a frequent cellphone user would get.
The study said there were some tissue and DNA issues but ‘‘we don’t feel sufficient understanding to comment on their biological significance’’. Washington Post