July 13, 2008
Frequent users of cellular phones develop tumors of the parotid gland 50 percent more often than less frequent users, according to a new study published in the American Journal of Epidemiology.
|Researchers found that people who used mobile phones for more than 22 hours each month had a 50 percent higher risk of developing parotid gland tumors.|
Researchers at the Chaim Sheba Medical Center in Israel examined data that included 402 cases of benign and 58 cases of malignant tumors of the parotid gland, the largest of the salivary glands. They found that people who used mobile phones for more than 22 hours each month had a 50 percent higher risk of developing parotid gland tumors. This risk increased among users who always held the phone to the same ear, who did not use handheld devices and who lived in rural areas.
“Analysis restricted to regular users or to conditions that may yield higher levels of exposure (e.g., heavy use in rural areas) showed consistently elevated risks,” the researchers wrote.
Tumors formed more frequently on the side of the head that patients most frequently held their phones to.
The study adds to emerging evidence that long-term cellular phone use increases the risk of cancers and tumors. Because many cancers do not appear for 10 years after initial exposure to a carcinogen, many of the early industry-sponsored studies finding mobile phones to be safe have been criticized for their lack of scope and failure to examine long-term use.
Two studies have found increased risk of a highly dangerous type of brain cancer known as glioma from long-term cell phone use. In an English study, people who used cell phones for more than 10 years were found to have a 20 percent higher risk of glioma, while a similar German study found the risk to be elevated by 100 percent.
A 2004 Swedish study found that frequent users of mobile phones had a higher risk of developing noncancerous brain tumors known as acoustic neuroma.