Scientific Flaws of the WHO Review on Cell Phone Radiation Cancer Risk

As an example, the Karipidis et al. review relied on the follow-up of the Danish cohort study (Frei et al 2011) which was based on cell phone subscriptions and lacked information on actual hours of phone use. Numerous experts have criticized the study design.  Corporate subscribers, who were likely the most heavy cell phone users at that time, were excluded and misclassified as unexposed (Söderqvist, Carlberg, and Hardell 2012). 

Importantly, the International Agency for Research on Cancer (IARC) RF working group downplayed the Danish cohort study in their 2011 evaluation stating that the cohort studies “lacked information on level of mobile-phone use and there were several potential sources of misclassification of exposure” (IARC 2013 Volume 102 page 419, See also page 169 of IARC 2024). 

The Karipidis review included primary studies that had simplistic categories of cell phone use such as “ever” versus “never” or “time since start” of use. These categories do not reflect a person’s actual exposure, and therefore do not address any actual dose-response relationships that might exist, again reducing the strength of the evidence for causation (Bradford Hill, 1965).  

Further, the cumulative call time analysis was underpowered because their statistical model included too few studies with substantial hours of cell phone use. They did not present a power analysis or goodness of fit statistics for this model. In spite of those shortcomings, a 30% increase in risk of glioma was observed after 1400 cumulative hours of use, with a linear increase in risk beginning after about 400 hours of cell phone use.

The time-trend simulations the authors cited to validate their conclusions are unable to capture the unique use and exposure characteristics of the groups in which brain tumor cancer risks were increased in the case-control studies such as increased tumor cancer risks in the areas of the brain (temporal lobe) with the highest absorption of RF radiation emitted from a mobile phone held next to the head. 

Inexplicably, the authors failed to cite high-quality studies showing clear increases in population rates of brain tumors in recent decades (Philips et al., 2018; Hardell and Carlberg, 2017; Zada et al. 2012; Defossez et al., 2019). 

The authors failed to follow standard guidance for pooling (combining) the results of primary studies. It is contraindicated to pool results among studies with such high levels of inconsistency (Ioannidis, 2018). They also pooled the results of fewer than five primary studies on a given research question, again, breaching widely-used statistical guidance (Valentine et al., 2017). These failings all have the effect of making the scientific certainty of their conclusions appear much greater than it actually is.  

The review’s conclusions of no cell phone brain cancer risk are not scientifically justified as the reviewed studies did not follow people for sufficient duration to diagnose late developing cancers. Cancers can take decades to be diagnosed. 

The International Agency for Research on Cancer Monographs Preamble (page 22)  states “experience with human cancer indicates that the period from first exposure to the development of clinical cancer is sometimes longer than 20 years; therefore latent periods substantially shorter than 30 years cannot provide evidence for lack of carcinogenicity.” 

None of the Karipidis et al. reviewed studies considered today’s real world exposures, of hours every day to multiple sources (phones, cell towers, Wi-Fi routers, Bluetooth and “smart” electronics) for 20 or 30 years. Furthermore, children born today will be exposed for a lifetime and Hardell and Carlberg (2015) found that first use of wireless phones before the age of 20 gave higher risk for glioma in the temporal lobe than in later age groups. 

However, Karipidis stated in his CNN article about the review that, “we can now be more confident that exposure to radio waves from mobile phones or wireless technologies is not associated with an increased risk of brain cancer,” and in his press conference that, “we can be quite confident there is no association between mobile phone use and brain cancer,” despite the fact that the review did not include studies with sufficient long-term cell phone use data to justify these safety assurances. 

Notably, some of the Karipidis et al. authors had previously acknowledged such uncertainty regarding cancer development for long latency periods, rare brain cancer subtypes, and childhood usage, and yet these uncertainties were not addressed nor resolved in the current review and analysis.