Confused by whom to believe? The World Heath Organization? The Wall Street Journal? Business Insider? The Huffington Post? We've chosen to go with the Environment Health Trust (putting us on the side of The Atlantic), which reported on the news Wednesday that an article in the Journal of the National Cancer Institute refutes prior claims that cell phone use by kids may cause brain tumors.
Results of student in the JNCI:
Regular users of mobile phones were not statistically significantly more likely to have been diagnosed with brain tumors compared with nonusers (OR = 1.36; 95% CI = 0.92 to 2.02). Children who started to use mobile phones at least 5 years ago were not at increased risk compared with those who had never regularly used mobile phones (OR = 1.26, 95% CI = 0.70 to 2.28). In a subset of study participants for whom operator recorded data were available, brain tumor risk was related to the time elapsed since the mobile phone subscription was started but not to amount of use. No increased risk of brain tumors was observed for brain areas receiving the highest amount of exposure.
Conclusion The absence of an exposure–response relationship either in terms of the amount of mobile phone use or by localization of the brain tumor argues against a causal association.
As The Atlantic reports:Case closed, right? Maybe not. Both the Environmental Working Group (EWG) and the Environmental Health Trust (EHT) have taken up arms against the study's results, arguing that poor data and methodological flaws render the findings problematic. Among the organizations' complaints:
- Failure to examine the consequences of long-term use. The EWG points out that only 5 percent of the participants in the study had used cell phones for more than five years. In the words of EHT president Devra Davis, "Given the restricted time-frame of the JNCI study, the absence of brain tumor risk from cell phones in children and adolescents is precisely what is expected." She adds, "If you asked whether people who had smoked only four years had an increased lung cancer risk, you would come up empty-handed." According to the EWG, studies of adults have found statistically significant increases in cancer risk only in people who have used cell phones for more than 10 years.
- Weak definition of "regular" phone use. The researchers defined "regular" phone users as "all subjects who had an average of at least one call per week for at least 6 months." The EWG argues that "[a]s nearly every cell phone user would affirm, one call a week is an extraordinarily low, and hardly typical, frequency of use," making it hard to generalize the results of the study to people in the real world, who presumably use cell phones more often.
- Media coverage ignores small but significant red flags. The EWG draws attention to a sentence from the study that indicates that when the researchers looked at the relatively small number of patients for whom phone company data were available, they found a "statistically significant trend of increasing risk with increasing time since first subscription." In other words, the greater the amount of time the children and adolescents had had their phones, the more likely they were to be at risk.