In 1999, Sharesa Price, a cell phone programmer in Northern Calif. became violently ill. Her head and eyes hurt and she couldn’t quit vomiting. Hours after a trip to her doctor Price learned she had a brain tumor. In 2005, she became the first United States citizen to convince a judge that her brain cancer was caused by cell phone exposure.
Since the mid-1990s, numerous studies have investigated the relationship between cellular telephone use and the risk of developing malignant and benign brain tumors. The latest of those major studies—conducted by the World Health Organization’s International Agency for Research on Cancer— is being published today in the International Journal of Epidemiology. The study found the cell phone-cancer link to be inconclusive.
Dubbed the Interphone Study, it surveyed nearly 13,000 participants over 10 years and found most cell phone use didn't increase the risk of developing meningioma — a common and frequently benign tumor — or glioma — a rare but deadlier form of cancer.
As of 2009, there were 1.6 billion cell phone users worldwide, according to International Telecommunication Union annual report. Globally, cell phone users are expected to reach a staggering 4.5 billion by 2012. Health concerns have been raised about cell phones due to the radio-frequency waves they emit. With respect to cancer, concern focuses on whether cell phones might increase the risk of brain tumors or other tumors in the head and neck area.
According to the Interphone International Study Group, there were “suggestions” that heavy cell phone users—those chatting for more than 30 minutes each day— could increase their risk of glioma by as much as 89 percent.
Jack Siemiatycki, a professor at the University of Montreal and an epidemiologist at the University of Montreal Hospital Research Center collaborated in the Interphone Study. He called the findings “paradoxical.”
“If we combine all users and compare them with non-users, the Interphone Study found no increase in brain cancer among users. In fact, surprisingly, we found that when we combine users independently of the amount of use, they had lower brain cancer risks than non-users. However, the study also found heavy users of cell phones appeared to be at a higher risk of brain tumours than non-users.”
David Carpenter, head of University of Albany’s Institute for Health and the Environment in Rensselaer, N.Y., similarly found it “perplexing” that apparent protective effect of cell-phone use for all but the longest, heaviest users. In fact, he said, “This cannot be real and probably is a reflection of some flaw in the design of the study,” one that he says “results in an artificial lowering of the reported risk.”
The study concedes this is a possibility. Dr. Siemiatycki argued this problem arose because of constraints imposed on researchers by ethics committees intended to protect potential research subjects. “This flawed system can produce biased study results,” he said in a released statement.
Carpenter pointed out the authors find a clear elevation in risk of brain cancer with prolonged use, especially for gliomas and tumors occur on the same side of the head as a user typically holds his or her phone. “This conclusion is exactly what has been reported in the earlier studies,” he said. As such, he contends, the paper’s general claim that there is no increased brain-tumor risk among cell users is “certainly cautious, and in my judgment, excessively cautious.”
In an editorial accompanying the paper, Rodolfo Saracci of the National Research Council in Pisa, Italy, and Jonathan Samet of the University of Southern California in Los Angeles argued that the authors attempted to finesse their interpretations in a way that did not unduly scare cell-phone users — even if their findings didn’t warrant such caution.
“None of today’s established carcinogens, including tobacco, could have been firmly identified as increasing risk in the first 10 years or so since first exposure.” Tumors among the Interphone study’s participants were diagnosed between 2000 and 2004 — even though wide-scale cell-phone use got underway only in the mid-1990s. So fewer than five percent of meningiomas and nine percent of gliomas occurred among people who had used cell phones 10 years or more.
For now, Saracci and Samet concede, the Interphone study “tells us that the question as to whether mobile phone use increases risk for brain cancers remains open.”
Lynette Summerill is an award-winning writer who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.
Study Source: The INTERPHONE Study Group. Brain tumour risk in relation to mobile telephone use: results of the INTERPHONE international case-control study. International Journal of Epidemiology, 2010; 1-20 DOI: 10.1093/ije/dyq079