Link Between Long-Term Cell Phone Use and Brain Tumors

NEW YORK OCT 02, 2007 (Reuters Health) - Using a cell phone for more than a decade can double the risk of some brain tumors, according to a new analysis of previous studies.

The findings "give a consistent pattern of increased risk for acoustic neuroma and glioma," Dr. Lennart Hardell of University Hospital in Orebro, Sweden and colleagues write, with the greatest risk seen on the side of the head where the mobile phone was held.

Acoustic neuromas are benign growths on the nerve linking the ear to the brain, while gliomas are malignant, difficult-to-treat tumors of the brain and nervous system.

Concerns have been raised that mobile phones could boost brain tumor risk by exposing the brain to electromagnetic energy, but early studies did not have a long enough follow-up time to fully account for long-term risk, Hardell and his team report in Occupational Environmental Medicine.

Enough time has now passed since mobile phones were introduced to analyze risks of cell phone use for 10 years or longer, which they believe is a "reasonable minimum period" to estimate risk.

Hardell and his team identified 18 studies of brain tumor risk among long-term cell phone users, 11 of which provided data for 10 years or longer. When the findings were analyzed collectively, the researchers found people who used cell phones for at least a decade had a 2.4-fold greater risk of acoustic neuromas and were twice as likely to develop gliomas.

One study found no increased tumor risk with cell phone use, but it did show that mobile phone users who developed brain tumors had larger tumors than non-cell phone users.

"These results are certainly of biological relevance." The greatest risk was for tumors located in the area of the brain with the most exposure and the study periods allowed enough time for tumors to develop, the researchers note.

They add that "longer follow-up is needed, however, as an increased risk for other types of brain tumors cannot be ruled out."

SOURCE:

• Occupational Environmental Medicine, September 2007.