A new study has concluded that long-term use of both mobile and cordless phones is associated with an increased risk of developing a glioma, the most common form of brain tumour.

The research showed that the risk for glioma was tripled among those using a wireless phone for more than 25 years, and that the risk was also greater for those who had started using a mobile or cordless phone before they had reached the age of 20 years old.

In the research article published in the medical journal PathoPhysiology, the research author, a professor in the Department of Oncology at the University Hospital in Orebro, Sweden, alerted doctors and warned that they should discuss precautions with their patients, including using hands-free phones with the ‘loud speaker’ feature, and text messaging, instead of talking.

THE POOLED STUDY DATA

The worldwide increase of wireless communications in recent years has resulted in greater exposure to radio-frequency electromagnetic fields, with the brain being the main target during phone use. The highest exposure to the electromagnetic fields occurs on the same side of the brain where the phone is placed. The study looked at the data from two case-control studies, with cases that came from six oncology centres in Sweden, and examined malignant brain tumours that were confirmed after histopathological examination. The first included patients aged 20 to 80 years old that were diagnosed from 1997-2003, and the second study included persons aged 18-75 years, diagnosed between 2007 and 2009.

The analysis included 1,498 cases of malignant brain tumours, where the mean age of the patients was 52 years. Ninety-two per cent of the patients had a diagnosis of glioma, of which one-half was the most malignant variety (astrocytoma grade IV).

The analysis also showed that an increased risk for glioma was associated with the use of both mobile and cordless phones for more than a year, and the highest risk was for those who had used mobile phones for over 25 years. Further, the risk was increased with greater use of wireless phones, and the risk for glioma was greatest in the most exposed part of the brain. Also, the risk was highest among participants who first used a mobile or cordless phone before age 20, although the number of cases seen in this category was relatively small.

THE DEVELOPING BRAIN

Children and adolescents are more exposed to the electromagnetic fields because of the thinner bones in their skull, their smaller heads, and the higher conductivity of their brain tissue. The brain is still developing up to around age 20, and so, until that time, it is relatively vulnerable. The researcher also found that there was a higher risk from the use of third-generation (3G) mobile phones compared to other types, and that 3G universal global telecommunications system mobile phones emitted wide band microwave signals that hypothetically may result in higher biological effects compared to other signals.

The researcher believes the new findings reinforce the message that electromagnetic emissions from wireless phones should be regarded as carcinogenic under the International Agency on Research on Cancer (IARC) classifications, and that current guidelines for exposure should be urgently revised to reflect this discovery. According to the IARC’s 2013 report, there is a “causal” relationship between use of both mobile and cordless phones and that risk of glioma is “possible”.

NOT YET CONVINCED

Numerous studies in the past have looked at the link between wireless phones and brain tumours. Some dating back to the late 1990s have found a connection with mobile and cordless phones. However, other researchers, while they acknowledge that this new study provides additional evidence of a potential role of cell and cordless technologies in the causing of gliomas, are as yet not fully convinced. They state that both glial and Schwann cells in the brain are late-responding tissues, and that how mobile phone technologies serve to bring about changes in the cells to cause cancer is yet to be explained.

Consequently, they argue that, while the potential role of cellphones as an additional factor in causing cellular change towards cancer in the brain cannot be ruled out, the use of this technology saves lives in other ways. Cellphone use has provided a large safety net for citizens in nearly all cultures around the world, and the lives saved by the proliferation of cell phone communication has occurred through emergency calls, quick responders, and warnings of severe upcoming weather, among other benefits.

This, notwithstanding, do the benefits outweigh the risks?

Derrick Aarons MD, PhD is a consultant bioethicist/family physician, a specialist in ethical issues in medicine, the life sciences and research, and is the ethicist at the Caribbean Public Health Agency – CARPHA. (The bioethical views expressed here are not written on behalf of CARPHA)