Case-control study on occupational exposure to extremely low-frequency electromagnetic fields and glioma risk

Exposure to extremely low-frequency electromagnetic fields (ELF-EMF) was in 2002 classified as a possible human carcinogen, Group 2B, by the International Agency for Research on Cancer (IARC) at WHO. In the international Interphone study on mobile phone use and glioma risk, glioma was associated with occupational ELF-EMF exposure in recent time windows. The authors concluded that such exposure may play a role in late stage carcinogenesis of glioma.

We assessed life time occupations in case-control studies during 1997-2003 and 2007-2009 on e.g. use of wireless phones and glioma risk. An ELF-EMF Job-Exposure Matrix was used for associating occupations with ELF exposure (μT). Cumulative exposure (μT-years), average exposure (μT), and maximum exposed job (μT) were calculated.

Cumulative exposure gave for astrocytoma grade IV (glioblastoma multiforme) in the time window 1-14 years before diagnosis odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.4-2.6, p linear trend <0.001, and in the time window 15+ years OR = 0.9, 95% CI = 0.6-1.3, p linear trend = 0.44 in the highest exposure categories 2.75+ and 6.59+ μT-years, respectively.

We concluded that we found an increased risk in late stage (promotion/progression) of astrocytoma grade IV for occupational ELF-EMF exposure. No statistically significant interaction was found between exposure to ELF-EMF and use of wireless phones (exposure to radiofrequency radiation; RF-EMF). They were independent risk factors for astrocytoma grade IV.

Decreased survival in patients with glioblastoma multiforme associated with use of mobile and cordless phones

In a new study a decreased survival was found in glioblastoma patients with long-term use of mobile and cordless phones. The study is free to download here.

According to the study 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, a decreased survival. 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. Due to the relationship with survival the classification of IARC (possibly carcinogenic to humans, Group 2B) is strengthened and RF-EMF should be regarded as human carcinogen requiring urgent revision of current exposure guidelines. The findings are discussed in detail in the article.

Mobile phone use is associated with decreased survival in patients with glioblastoma multiforme (astrocytoma grade IV)

The p53 protein is a transcription factor that plays a vital role in regulating cell growth, DNA repair and apoptosis, and p53 mutations are involved in disease progression. In a recent study it was found that use of mobile phones for ≥3 hours a day was associated with increased risk for the mutant type of p53 gene expression in the peripheral zone of astrocytoma grade IV. The mutation was statistically significant correlated with shorter overall survival time. The study was rather small (n=63) and no data on latency of mobile phone use was given.

We have previously reported decreased survival in patients with glioblastoma multiforme associated with use of mobile phones. The present study supports our findings and gives insight into a possible genetic mechanism both for the increased risk for glioblastoma multiforme and the decreased survival.