MONDAY, April 22, 2002 (HealthDayNews) -- If, like many folks, your cell phone has become your main source of communication, you'll be happy to hear that one more study shows it's not likely to increase your risk of head tumors.
Reporting in tomorrow's edition of Neurology, doctors from a number of top New York medical centers found no link between cell phone use and acoustic neuromas, which are tumors that form along the nerve pathway from the brain to the ear.
However, physicians not involved in the study who reviewed the research -- and even the study authors themselves -- say they are not completely convinced of phone safety.
"I would by no means call our data conclusive, or say that there is absolutely no risk involved in phone use," says Roy Shore, study co-author and director of the Epidemiology and Biostatistics program at New York University School of Medicine.
"There are 120 different types of brain tumors," adds renowned brain surgeon Dr. Keith Black, director of Division of Neurosurgery and Neurosurgical Institute at Cedars Sinai Medical Center in Los Angeles.
"I think you need studies looking at a much larger patient population, and over a much longer period of time, before you can draw any conclusive decisions about cell phone safety," he adds.
Acoustic neuromas are benign tumors that form on a nerve pathway leading from the brain to the inner ear, often affecting hearing and balance. The idea that cell phones might cause these tumors grew from the concept that radiation from the phones is superficially absorbed into the skin and bones surrounding the ear, and the bone behind the ear.
"We wanted to see if there was a connection between phone use and tumor development, particularly since these phones are so widely used," Shore says. In the United States, an estimated 118 million people have cell phones.
The new study, which also involved physicians from Columbia Presbyterian Medical Center, Memorial Sloan-Kettering Cancer Center and The American Health Foundation, looked at 176 patients whose average age was 54. Ninety of the patients were diagnosed with acoustic neuromas; 86 had no tumors and acted as the control group.
Both groups answered questionnaires detailing their medical history and lifestyle, including factors such as smoking, alcohol consumption and occupational exposures.
Questions also detailed cell phone use, including years of use, minutes/hours per month of use, year of first use, phone manufacturer and total monthly costs. They also were asked which hand they generally used to hold the phone.
Ultimately, researchers identified 18 acoustic neuroma patients and 23 people in the control group who regularly used a hand-held phone, bringing the final study group number to 41 men and women. The patients used the phones, on average, 4.6 hours a month for 4.1 years, while the control group used their phones 6.6 hours per month for 2.2 years.
After adjusting for age, education, sex, study center, occupation and date of interview, Shore reports no association between the tumors and phone use could be found.
"The risk of acoustic neuroma was unrelated to the frequency and duration of cellular telephone use," Shore says.
While there remained a slightly higher risk among patients who used the phone more than three years, Shore says when cumulative use was tallied, no correlations were found.
For Black, the data remains unconvincing.
"None of these studies can conclusively show that the use of cell phones does not cause brain tumors, and we still are left with a situation in which, at this time, we have no data to conclusively show that either cells phones are safe for use or not safe for use," Black says.
Black is also concerned there may be a subgroup of patients who are susceptible to cell phone effects who have not yet been identified.
"What we currently know about the development of cancer is related both to environmental influences as well as genetic influences," he says. "So, there very well could be a subpopulation of patients prone to developing brain tumors with the use of cell phones, and right now we just don't have enough information to make that determination."
Shore agrees, and openly acknowledges the limitations of his research: "Cell phones simply haven't been in use long enough to draw any conclusions about safety with long-term use."
Both researchers continue to issue cautions on cell phone use, with Black adding that he uses an ear wire for his phone, rather than placing the device next to his head -- a move he believes reduces microwave transmissions near the brain.
This study also involved researchers from Bristol-Myers Squibb Co., and was co-sponsored by the National Cancer Institute and a research fund established by Wireless Technology Inc., a consortium of companies involved in the cell phone industry.
What To Do
For more information on cell phone safety, check out this report from ABC News.
To learn more about acoustic neuromas, visit Johns Hopkins Radiosurgery.
