Mobile phone use is not linked to brain tumours, large Scandinavian study findsBMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b5323 (Published 07 December 2009) Cite this as: BMJ 2009;339:b5323
Mobile phone use rose dramatically in the early 1990s, but five to 10 years later there was no increase in the incidence of brain tumours in Denmark, Finland, Norway, and Sweden, a new study has found.
The authors of the study, published in the Journal of the National Cancer Institute (2009;101:1721-4, doi:10.1093/jnci/djp415), wrote, “Radio frequency electromagnetic fields emitted from mobile phones have been proposed as a risk factor for brain tumors; however, a biological mechanism that could explain the potential effect of radio frequency electromagnetic fields in the risk of brain tumors has not been identified.”
If mobile phones caused brain cancers, the number of cancers should have risen 5-10 years after exposure, they say, but “no change in incidence trends [of brain cancers] was observed from 1998 to 2003, the time when possible associations between mobile phone use and cancer risk would be informative about an induction period of 5-10 years.”
The study was based on nearly 60 000 cases of brain tumours diagnosed from 1974 to 2003 among 16 million people, the entire population of the four Nordic countries, which have good cancer registry information.
The authors, from cancer institutes and schools of public and environmental health in the four countries, say that mobile phone use became widespread in the early 1990s and increased sharply in the mid-1990s in the four countries. They used data from national cancer registries for the rates of brain tumours such as meningiomas and gliomas from 1974 to 2003 in all four countries.
From the mid-1970s to the mid-1980s the numbers of brain tumours diagnosed in patients aged 20-79 were stable or rose slightly. The authors say that this increase may be due to better diagnosis with the availability of computed tomography and magnetic resonance imaging for patients complaining of dizziness and headaches.
The lack of an association between brain cancers and mobile phone use, the authors write, suggests that the induction period from mobile phone use may be longer than 5-10 years, the increased risk may be too small to be seen, the risk may be restricted to subgroups of brain tumours or phone users, “or there is no increased risk.”
Cite this as: BMJ 2009;339:b5323