The same group of international health researchers who warned the world in May that mobile phones might cause cancer have a bit of good news to share: cell phones apparently don't cause certain non-cancerous brain tumors.
As published in the American Journal of Epidemiology, researchers from the International Agency for Research on Cancer (IARC) examined data on over 2.8 million Danish adults and discovered no increased likelihood that those who used a mobile phone for 11 to 15 years were prone to a type of slow-growing tumor known as a acoustic neuroma (also called vestibular schwannoma). These tumors occur in the part of the brain most exposed to electromagnetic fields from cell phone use.
If cell phones caused brain tumors, those who used them longest should have an increased risk of getting them, particularly on the side of the head where they hold their phones. Not so, the researchers found. Out of the 2.8 million studied, 800 people developed acoustic neuroma tumors but those who used mobile phones for at least 11 years were not represented in greater numbers than shorter-term or non-users. Among women who were long-term mobile phone users, no cases of acoustic neuromas were diagnosed. Of the long-term users who grew ill, the tumors were not larger than expected nor did they occur more frequently on the sides of the head that participants reported to have held them on.
"Overall, no evidence was found that mobile phone use is related to the risk of vestibular schwannoma," the researchers wrote. However, they aren't giving the all-clear signal yet; because these are slow-growing tumors, they say it is possible that 11 years isn't a long enough time to know for sure.
Last May the IARC issued a statement warning that use of mobile phones was officially classified as "possibly carcinogenic" to humans. The IARC was guarded in this warning, as the evidence hasn't exactly been smacking researchers in the head with a clear-cut, cause-and-effect link.
Even in that warning, the organization said that the evidence showing risk of brain cancer was "limited" and only seemed to indicate a specific type of cancer, known as glioma. At that time, they also felt that evidence showed a similar danger of acoustic neuroma tumors: according to the IARC press release, "past cell phone use (up to the year 2004)... showed a 40% increased risk for gliomas in the highest category of heavy users (reported average: 30 minutes per day over a 10-year period)." However, with this latest research to add to the bucket, it is looking like mobile phones are innocent of causing acoustic neuromas.