A new study from the U.K. is adding support to the still controversial proposition that long-term use of a cell phone increases the risk of developing acoustic neuroma, a tumor of the acoustic nerve. No higher risk of glioma or meningioma, two types of brain cancer, was observed. Women who used a mobile phone for more than ten years were two-and-half-times more likely to have an acoustic neuroma than those who never used a phone. The finding is statistically significant.
"[W]e did find a trend of increasing risk of acoustic neuroma with increasing duration of mobile phone use," according to the team led by Victoria Benson, Jane Green and Valerie Beral of the University of Oxford. IARC's Joachim Schüz, who has long argued that cell phones do not present a tumor risk, is a coauthor. The trend of more tumors with more phone use is also statistically significant. The paper is being published by the International Journal of Epidemiology; a copy was posted on its Web site on May 8th.
Amazingly, the finding of an increase in acoustic neuroma is omitted in the study conclusions presented in the published abstract. Only the lack of an association with brain cancer is reported there. Two other epidemiological studies have seen a link between acoustic neuroma and long-term cell phone use.
But perhaps the most controversial aspect of the new study is that it is being called a "prospective study." It is true that the women were recruited before they developed a tumor, but nothing about the assessment of phone use could be called prospective. Cell phone epidemiological studies have long been criticized because of the uncertainties inherent in people estimating how often they used a cell phone after they developed a tumor. In this regard, the new U.K. study offers scant improvement over past efforts.
"The evidence presented is less than a slam dunk," said Joe Bowman, an industrial hygienist with theU.S. NIOSH, who worked on the Interphone study. "The exposure assessment in the new study was pretty crude and no attempt was made to estimate radiation exposure," he told Microwave News from his office in Cincinnati. "While it is better than in past retrospective studies in some ways, it is worse in others," he added. "For example, in Interphone, a user's entire phone history was obtained."
Cell phone use was based on the answers to only one or two questions posed at the time the women were recruited for the study. They were asked, "About how often do you use a mobile phone?" and were given three options: "never," less than once a day" and "every day." Those who did use a cell phone were also asked "for how long?" At the end of the study in 2009, participants were asked two more questions about their cell phone use, but those answers were not used in the data analysis.
"The study has extremely limited exposure assessment," concurred Joel Moskowitz, an epidemiologist at the University of California, Berkeley. In 2009, Moskowitz published a meta-analysis pointing to a tumor risk from cell phones. In an interview, Moskowitz pointed out that the U.K. team had not collected any information on the use of cordless phones. "This could have been an important source of RF exposure," he said.
The Oxford paper also reports a higher than expected incidence of tumors of the pituitary gland, but this increase is not statistically reliable.
Both the Interphone project and the studies of Lennart Hardell in Sweden have previously linked long-term cell phone use with acoustic neuroma. Last fall, the Italian Supreme Court ruled in favor of such an association.
Two years ago, an expert panel convened by IARC classified RF radiation as a possible human carcinogen. In April, IARC published the rationale for the decision.
Source: http://microwavenews.com/short-takes-archive/uk-study-points-acoustic-neuroma-not-glioma-risk
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