This is a review and combined analysis of studies assessing whether radiofrequencies increase the risk of cancers in people. Radiofrequencies (RF) refers to electromagnetic energy in the wavelengths of 300 Hz to 300 GHz, that is, a lower frequency and lower energy than visible light. RF is used for mobile phones and radio and TV. It is also used in baby monitors, wi-fi connections, radar, and many industrial and medical uses.

The study has 11 investigators, from 10 countries. The work was set up by the World Health Organization (WHO), and has taken four years from design to publication of results. For this report, cancers of the brain (three types, and in children), pituitary gland, salivary glands, and leukaemias were included. Other cancer types will be reported separately.

All studies published from 1947 to 2022 were assessed. 63 relevant articles were found, from 22 countries, reporting on 119 relationships (that is, one type of RF and one type of cancer). Each of these 119 was assessed, using pre-set methods and assessment of the quality of each study.

None of the major questions studied showed increased risks. For the main issue, mobile phones and brain cancers, we found no increased risk, even with 10+ years exposure and the maximum categories of call time or number of calls.

We also assessed 13 studies from 12 countries studying whether more brain cancers were occurring in recent years, along with more cell phone use: these studies showed no major increases. Similarly, we found no increased risks of leukaemia or brain cancers in children in relationship to radio or TV transmitters or cell phone base stations. We also found no increased risk of brain cancers with occupational exposures in the manufacture or operation of equipment.

For mobile phones and brain cancers, there were studies with 10 or more years’ use, and quite extensive use. Most phone use in these studies was from past years and 1G -2G networks; the newer 3G-4G networks have substantially lower RF emissions. There were several studies that reported some increased risks, but these were outweighed in considering all the available evidence.

There are no major studies yet of 5G networks, but there are studies of radar, which has similar high frequencies; these do not show an increased risk.

Some questions cannot be answered as there are not sufficient studies available: for rare types of cancer or unusual types of exposure. Small increases in risk cannot be assessed.

The final assessments are that there are no increased risks, with ‘moderate confidence’. In the scheme we used, this is the most definite category for observational studies. The only higher category, ‘high confidence’ is only used for questions where randomised experimental studies (clinical trials) have been done.

We are monitoring new studies published since our main cut-off, December 2022. There have been several, including the first report on cancer from the COSMOS international cohort study, with over 250,000 participants. These studies are in general consistent with our conclusions.

This is a very comprehensive review by an esteemed international group that reviewed the available evidence for the effects of radiofrequency on risk of brain and related cancers. They found the evidence did not support an increased risk of cancers from the use of mobile phones. Furthermore, there was no evidence to support any risk from broadcasting transmitters or base stations.

Worries about the health effects of new technology are common and tend to increase when a new technology is adopted widely or adopted quickly. This was seen during the COVID-19 pandemic when people attacked cell towers believing a baseless theory that 5G towers spread the coronavirus. Similar anxieties were evident after the rapid development of the COVID vaccines based on new messenger RNA technology. For example, there was widespread anxiety based on misinformation that the COVID vaccines caused disease or contained a microchip.

There are also a small group of people who attribute physical symptoms to electromagnetic fields from cell phones or wifi or believe they are hypersensitive to electromagnetic fields. There now have been a large number of controlled double blind studies, where the individuals do not know when they are being exposed or not to electromagnetic fields. The results of this work show that participants and even 'hypersensitive' individuals cannot reliably tell when they are exposed. There has also no detectable differences on physiological responses or performance between the exposed and non-exposed groups.