Regular cell phone use may increase the risk of developing persistent ringing in the ear - a condition known as tinnitus, a small Austrian study suggests.
But one U.S. ear specialist called the data used for the study "very weak," adding that the study failed to prove a connection between cell phone use and tinnitus.
The study's lead researcher, Dr. Hans-Peter Hutter of the Institute of Environmental Health at the Medical University of Vienna, said "high intensity, long duration of mobile phone use might be associated with occurrence of tinnitus. Therefore, we are recommending a far more conscious and cautious way of using mobile phones."
The study authors cited studies showing that tinnitus affects 10 percent to 15 percent of people in the developed world, and they said that number is increasing. The condition can severely affect quality of life for many sufferers, and little can be done to reduce the troublesome ringing, hissing or roaring.
Read: A visual guide to tinnitus
For the study, published online July 19 in the journal Occupational and Environmental Medicine, Hutter's team studied 100 people treated for chronic tinnitus and 100 without it. The participants were asked a variety of questions about their cell phone use.
Based on the participants' responses, the researchers estimated that people who used a cell phone before the first symptoms of tinnitus appeared were 37 percent more likely to develop the condition than those in the control group. Also, people who used their cell phone for at least 10 minutes a day were 71 percent more likely to develop tinnitus than the other study participants.
Most people in the study used their cell phones on both ears, but tinnitus typically affected one ear - 38 percent of participants mentioned the left ear and about the same percentage said it distressed them most of the time. Twenty-nine percent reported also suffering from vertigo, or dizziness.
The researchers said that the high amount of microwave energy being absorbed by the cochlea in the inner ear might explain the possible connection.
Hutter said loud noise is the main risk factor for tinnitus. But, he added, "we are observing a widespread use of mobile phones and an increasing intensity of use. Therefore, even a small enhancement of the risk by mobile phone use could be of public health importance."
Dr. Thomas J. Balkany, director of the University of Miami Ear Institute, said this study failed to show that using cell phones causes tinnitus.
"The data are very weak," Balkany said. "They [the study authors] haven't looked into the common causes of tinnitus in the kind of detail that would be necessary. These include stress and anxiety and depression, [and] the huge impact of MP3 players," he said.
A weak relationship seems to exist between tinnitus and cell phone use, Balkany said, "but it's not causative in any way."
A much larger study would be needed to determine whether cell phones really can cause tinnitus, he said.
Hutter said protective measures are easily implemented to protect hearing. These include discouraging cell phone use by children and teenagers, using headsets, and reducing the number and length of cell phone calls.
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