Long-standing fears that using cell phones could increase the risk of developing a brain tumor have recently been revived by the launch of 5G (fifth generation) mobile wireless technologies. Mobile phones emit radio frequency waves which, if absorbed by tissue, can cause overheating and damage.
Since cell phones are held close to the head, the radio frequency waves they emit penetrate several centimeters into the brain, with the temporal and parietal lobes being the most exposed. This has led to fears that mobile phone users are at increased risk of developing brain tumours, with the International Agency for Research on Cancer (IARC) classifying radio frequency waves as “possibly carcinogenic”. However, most of the studies that have looked at this question to date are retrospective studies in which individuals report using a mobile phone after a cancer diagnosis, which means the results may be biased.
Today, researchers from Oxford Population Health and IARC reported the results of a large UK prospective study (a study in which participants are enrolled before developing the disease(s) in question) to investigate the association between mobile phone use and brain tumor risk. . The results are published in the Journal of the National Cancer Institute.
The researchers used data from the UK Million Women Study: an ongoing study that recruited one in four British women born between 1935 and 1950. Around 776,000 participants completed questionnaires about their mobile phone use in 2001; about half of them were interviewed again in 2011. Participants were then followed for an average of 14 years through linkage with their NHS records.
Mobile phone use has been examined in relation to the risk of various specific types of brain tumours: glioma (a tumor of the nervous system); acoustic neuroma (a tumor of the nerve connecting the brain and the inner ear); meningioma (a tumor of the membrane surrounding the brain); and tumors of the pituitary gland. The researchers also investigated whether cell phone use was associated with the risk of eye tumours.
- In 2011, almost 75% of women aged 60-64 used a mobile phone, and just under 50% of those aged 75-79
- During the 14-year follow-up period, 3,268 (0.42%) of the women developed a brain tumor
- There was no significant difference in the risk of developing a brain tumor between those who had never used a cell phone and cell phone users. These included tumors in the temporal and parietal lobes, which are the most exposed parts of the brain
- There was also no difference in the risk of developing glioma, acoustic neuroma, meningioma, pituitary tumors or eye tumors
- There was no increased risk of developing any of these types of tumors for those who used a cell phone daily, talked at least 20 minutes per week, and/or had used a cell phone for more than 10 years
- The incidence of right-sided and left-sided tumors was similar among mobile phone users, although mobile phone use tended to be significantly higher on the right side than on the left side
Co-investigator Kirstin Pirie from Oxford Population Health’s Cancer Epidemiology Unit said: “These results confirm the accumulating evidence that cell phone use under usual conditions does not increase tumor risk. cerebral.”
Although the results are reassuring, it is unclear whether the risks associated with mobile phone use are different among those who use a mobile phone significantly more than was typical of women in this cohort. In this study, only 18% of phone users reported talking on a mobile phone for 30 minutes or more each week. Mobile phone users for long periods of time can reduce their exposure to radio frequency waves by using hands-free kits or loudspeakers.
The study did not include children or adolescents, but researchers elsewhere have investigated the association between cellphone use and brain tumor risk in these groups, finding no association.
IARC Principal Investigator Joachim Schüz said: “Mobile technologies are constantly improving, so newer generations have significantly lower output power. Nevertheless, given the lack of evidence for heavy users, advising mobile phone users to reduce unnecessary exposures remains a good precautionary approach.
The study is published in Journal of the National Cancer Institute.
Reference: “Cellular Telephone Use and the Risk of Brain Tumours: Update of the UK Million Women Study” by Joachim Schüz, PhD, Kirstin Pirie, MSc, Gillian K Reeves, PhD, Sarah Floud, PhD, Valerie Beral, FRS, for the Million Women Study Collaborators, March 29, 2022, JNCI: Journal of the National Cancer Institute.
The study was funded by the UK Medical Research Council and Cancer Research UK.