Incidence of glioma and mobile phone use

What is the issue?

Isabelle Deltour and Joachim Schüz from the International Agency for Research on Cancer carried out the research project "Mobile phone use and time trends in glioma incidence since 1979" on behalf of the BfS/BMUV. The project is based on the following considerations: Exposure to electromagnetic fields from mobile communications has fundamentally changed in recent decades. Whilst hardly anyone owned a mobile phone before 1990, almost everyone uses one today. If mobile phone use does indeed increase the risk of glioma, this widespread use should have led to an increase in the number of new glioma cases (incidence rate). The project updates the analyses from Deltour et al. (2012) in which the period 1979 to 2008 was considered.

What is the current situation?

Epidemiological studies on the health consequences of mobile phone use mostly showed no association between mobile phone use and the risk of developing glioma, the most common type of brain tumour. However, a few older case-control studies reported an increased risk of glioma as a result of mobile phone use.

To investigate this question, incidence rates from the cancer registries of Denmark, Finland, Norway, and Sweden were used. These data were chosen for the study because health care, cancer diagnostics, and cancer registration are of particularly high quality in these countries. In addition, the ongoing international COSMOS (Cohort Study of Mobile Phone Use and Health) study is the first to compare mobile phone use with objective usage data from mobile phone operators.

What are the objectives of the BfS research project?

The project aims to determine whether the risk of disease is increased by mobile phone use. For this purpose, using the statistical approach of Deltour et al. (2012), the incidence rates in the Nordic countries from 1979 to 2016 will be evaluated. The objective usage data for mobile communications will be used to estimate exposure. The incidence trends of the simulation study determined in this way (assumption of various theoretical risk increases as a result of mobile phone use) will be compared with the actual incidence rates in order to be able to assess the risk of disease associated with mobile phone use.

What results did the research project provide?

For new glioma cases from the cancer registries of Denmark, Finland, Norway, and Sweden the number of individuals who developed glioma at a younger and middle age (20 to 39 years and 40 to 59 years, respectively) remained relatively constant between 1979 and 2016. However, in the age groups 60 to 69 years and 70 to 84 years, the annual glioma incidence rates continually increased during the study period.

Overall, the temporal development of glioma morbidity does not speak for an increase in the risk of glioma resulting from the use of mobile phones. If mobile phone use did increase the risk of glioma, a considerable increase in the incidence of glioma would have been expected from the 1990s onwards because mobile phone use increased sharply from that time onwards. However, in the period 1990–2016, no point in time at which the increases would have changed noticeably was identified. The increase in new glioma cases in the over-60-year-olds is more likely due to improved diagnostics and a better registration of cases.