Decreased Survival of Glioma Patients with Astrocytoma Grade IV (Glioblastoma Multiforme) Associated with Long-Term Use of Mobile and Cordless Phones

Abstract

On 31 May 2011 the WHO International Agency for Research on Cancer (IARC) categorised radiofrequency electromagnetic fields (RF-EMFs) from mobile phones, and from other devices that emit similar non-ionising electromagnetic fields, as a Group 2B, i.e., a “possible”, human carcinogen. A causal association would be strengthened if it could be shown that the use of wireless phones has an impact on the survival of glioma patients. We analysed survival of 1678 glioma patients in our 1997–2003 and 2007–2009 case-control studies. Use of wireless phones in the >20 years latency group (time since first use) yielded an increased hazard ratio (HR) = 1.7, 95% confidence interval (CI) = 1.2–2.3 for glioma. For astrocytoma grade IV (glioblastoma multiforme; n = 926) mobile phone use yielded HR = 2.0, 95% CI = 1.4–2.9 and cordless phone use HR = 3.4, 95% CI = 1.04–11 in the same latency category. The hazard ratio for astrocytoma grade IV increased statistically significant per year of latency for wireless phones, HR = 1.020, 95% CI = 1.007–1.033, but not per 100 h cumulative use, HR = 1.002, 95% CI = 0.999–1.005. HR was not statistically significant increased for other types of glioma. Due to the relationship with survival the classification of IARC is strengthened and RF-EMF should be regarded as human carcinogen requiring urgent revision of current exposure guidelines.

Introduction

1.1. Background

The use of both mobile and cordless phones has increased rapidly between the mid-1990s and early 2000s and has since then remained stable at a very high level. During use these devices emit radiofrequency electromagnetic fields (RF-EMFs) and also extremely low frequency electromagnetic fields (ELF-EMFs) from the battery [1–3]. The brain is the primary target organ for exposure to electromagnetic fields during the use of handheld phones. This has raised concerns about an increased risk for brain tumours. Many users are children and adolescents, which is of special concern regarding potential health effects on this population. On 31 May 2011 the WHO International Agency for Research on Cancer (IARC) categorised RF-EMFs from mobile phones, and from other devices that emit similar non-ionising electromagnetic fields, as a Group 2B, i.e., a “possible”, human carcinogen [4,5]. The IARC decision on mobile phones was based mainly on two sets of human case-control studies on brain tumour risk; our studies from Sweden [6–8] and the IARC Interphone study and also on available preprint studies [9–11]. Both provided complementary and supportive results on positive associations between two types of brain tumours; glioma and acoustic neuroma, and exposure to RF-EMFs from wireless phones.

1.2. Some Technical Aspects

The Nordic countries were among the first in the world to widely adopt wireless telecommunications technology. Analogue phones (Nordic Mobile Telephone System—NMT) were introduced in the 1980s using both 450 (1981 to 2007) and 900 (1986 to 2000) Megahertz (MHz) frequencies. The digital system (Global System for Mobile Communication—GSM) using two bands, 900 and 1800 MHz, started to operate in 1991 and now dominates the market. The third generation of mobile phones, 3G or Universal Mobile Telecommunication System (UMTS), using 1900/2100 MHz has been introduced worldwide during the last decade, and in Sweden in 2003. The fourth generation (4G; LTE) was introduced in parts of Sweden at the end of 2009. Desktop cordless phones have been used in Sweden since 1988, first using the analogue 800–900 MHz frequencies, but since the early 1990s using a digital 1900 MHz system (Digital Enhanced Cordless Telecommunications—DECT). These phones also emit RF-EMF radiation similar to that of mobile phones. Thus, it is necessary to consider the usage of cordless phones, along with mobile phones, when human health risks are evaluated.

1.3. Aim of the Study

The aim of this study was to analyse survival of glioma patients in our case-control studies in relation to use of wireless phones; mobile and cordless phones [6,8,12,13]. Survival was assessed using the Swedish population registry that is continuously up-dated. All inhabitants can be followed using the unique ID number for each subject. If deceased, date of death is recorded. All cases were followed from date of diagnosis based on the histopathology report until 18 December 2013 or if deceased, date of death. We have previously reported survival for patients with glioma in our case-control study for the time period 1997–2003 [14]. We have now up-dated these results with further follow-up of these cases and furthermore added our study for the time period 2007–2009 [13]. This publication covers both study periods with up-dated results on survival. It should be noted that all diagnoses were based on histopathology. Thus, all cases had undergone some type of surgery.

Read the full study below.