Using a mobile phone for 10 years does not significantly increase the risk of developing a tumor, according to a new study from the UK's Institute of Cancer Research.
The investigation was the biggest to date that has studied the relationship between mobile phones and a type of tumor that occurs close to the ear called an acoustic neuroma, according to the study's authors.
"The results of our study suggest that there is no substantial risk in the first decade after starting use. Whether there are longer-term risks remains unknown, reflecting the fact that this is a relatively recent technology," Anthony Swerdlow, professor and lead investigator at the Institute of Cancer Research, said in a statement.
The study looked at 678 people with acoustic neuromas and 3,553 people without the illness. They were asked detailed questions about their mobile phone use, including length and frequency of calls and the type of phone they used, and about other factors that could affect their risk of getting the disease.
The study found no relation between the risk of acoustic neuroma and how much people used their mobile phones.
Acoustic neuromas are of particular interest because they occur close to where mobile phones are held to the head. They are a type of benign tumor that grows in the nerve connecting the ear to the brain. Acoustic neuromas often cause hearing loss and impair balance, but they do not typically spread to other parts of the body.
The results concur with the findings of other recent reports, but since longer-term studies are advised, the U.K. study may still not put the debate to rest over whether cell phone radiation harms health.
Still, the test marks "a great step forward" in understanding the relationship between tumors and mobile phones because it involved such a large number of participants, the researchers said.
"The evidence for the health effects of mobile phones and radio-frequency fields in general has been reviewed by several expert committees quite recently, and the results of this new study are compatible with their conclusions," Minouk Schoemaker, one of the report's authors, wrote in an e-mail response to questions.
The study was published online Tuesday in the British Journal of Cancer. It was conducted in the U.K., Denmark, Finland, Norway and Sweden -- countries where mobile phones were introduced relatively early.
A separate study from Denmark, published in April in the journal Neurology, looked at two other types of tumor, glioma and meningioma. The study involved about 1,200 participants, including 427 suffering from one of the two diseases, and also found no increased risk from cell phone use. It too advised that longer-term data is required.
A further report released in January by the U.K.'s National Radiological Protection Board acknowledged there was no conclusive evidence linking mobile phones to tumors or cancer, but recommended limiting phone use by children. It suggested they may be more vulnerable to radio frequency radiation exposure because their nervous systems are still developing.
This week's UK study looked at people aged between 18 and 69 and did not address the risks to children, Schoemaker said.
The Institute is also studying other types of tumors, including glioma and meningioma. Results from those tests are not ready for release, she said.
Asked for her personal opinion about whether mobile phones pose a health risk, she replied that the greatest risk established to date is from the increased risk of accidents from using a cell phone while driving.