An increased risk of brain tumours has been detected in a study of long-term exposure to microwaves from cellular phones.
Though the debate on the effects of long-term use of cellular or cordless phones continues, independent studies have strongly suggested that there is an increased risk of brain tumours.
To gain insight into the controversy, R.B. Dubey, of Apeejay College of Engineering, Sohna, Gurgaon, India, and colleagues performed an in-depth analysis of research on the health risks associated with microwave exposure from wireless phones.
"We conclude that the current standard of exposure to microwave during mobile phone use is not safe for long-term exposure and needs to be revised," authors, who conducted the study, led by Dubey, said.
Some studies have reported that long-term wireless phone users have increased rates of brain tumours, including malignant gliomas and benign acoustic neuromas. However, other studies have found no association.
But an independent series of studies led by Swedish cancer specialist Dr. Lennart Hardell, on more patients who had used a cell phone for ten years or longer, reached a different conclusion.
The findings suggested that the more hours of cellular phone use over time, the higher the risk of developing brain tumours.
Risk also increased along with the level of power from the wireless device, years since first use, total exposure, and younger age when starting wireless phone use.
Based on an analysis of pooled data from different studies, researchers wrote that long-term cell phone usage can approximately double the risk of developing a glioma or acoustic neuroma in the more exposed brain hemisphere, that is, on the side where the user typically holds the phone to the ear.
That conclusion is consistent even with data on the long-term cell phone users from the Interphone studies.
It's unclear exactly how exposure to microwave radiation from cell phones may increase brain cancer risk. However, studies have shown that the cell signal is absorbed up to two inches in the adult skull.
There is special concern about the risks in younger age groups, as cell phone signals penetrate much deeper into the brain in children.
The findings have been published in the November/December issue of Journal of Computer Assisted Tomography.