A major U.S. government study has linked cell phones with an increased risk of cancer among male rats. The findings are certain to add new fuel to a long-burning controversy.
The study, run by the U.S. National Toxicology Program, observed a small but statistically significant uptick in the number of two types of cancer, gliomas in the brain and schwannomas in the heart, in male rats. Cancer incidence was unchanged in female rats.
A preliminary report was posted on the bioRxiv preprint server after an apparent leak to Microwave News . The heart and lung results were the only ones included in the current publication; effects on other parts of the body will be included in forthcoming submissions, the authors report.
The more than 2,500 rats and mice involved in the study were exposed to radio frequency radiation of varying strengths using the two different transmission techniques—GSM and CDMA—that have been used by cell phones since the 1990s.
The two tumor types found in the male rats are similar to those that have been reported in some population-wide human studies. Thus, the authors report, the National Toxicology Program study findings “appear to support” the WHO’s classification as a possible carcinogen.
It’s unclear why only male rats were affected by the cell phone signals, and as the NIH pointed out in a statement given to Megan Thielking and Dylan Scott at Stat News, previous population-wide studies on humans haven’t found only limited evidence of a link between cell phone use and cancer. Indeed, in several countries where cancer rates have been scrutinized, incidence of brain cancer hasn’t skyrocketed over decades of widespread cell phone use.
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