Future needs of occupational epidemiology of extremely low frequency electric and magnetic fields: review and recommendations

Abstract

The occupational epidemiological literature on extremely low frequency electric and magnetic fields (EMF) and health encompasses a large number of studies of varying design and quality that have addressed many health outcomes, including various cancers, cardiovascular disease, depression and suicide, and neurodegenerative diseases, such as Alzheimer disease and amyotrophic lateral sclerosis (ALS). At a 2006 workshop we reviewed studies of occupational EMF exposure with an emphasis on methodological weaknesses, and proposed analytical ways to address some of these. We also developed research priorities that we hope will address remaining uncertainties. Broadly speaking, extensive epidemiological research conducted during the past 20 years on occupational EMF exposure does not indicate strong or consistent associations with cancer or any other health outcomes. Inconsistent results for many of the outcomes may be attributable to numerous shortcomings in the studies, most notably in exposure assessment. There is, however, no obvious correlation between exposure assessment quality and observed associations. Nevertheless, for future research, the highest priorities emerge in both the areas of exposure assessment and investigation of ALS. To better assess exposure, we call for the development of a more complete job-exposure matrix that combines job title, work environment and task, and an index of exposure to electric fields, magnetic fields, spark discharge, contact current, and other chemical and physical agents. For ALS, we propose an international collaborative study capable of illuminating a reported association with electrical occupations by disentangling the potential roles of electric shocks, magnetic fields and bias. Such a study will potentially lead to evidence-based measures to protect public health.

Risk agents related to work and amyotrophic lateral sclerosis: An occupational medicine focus

“…However, in the case of electromagnetic fields, there are many problems: at present, no apparent correlation between the exposure assessment and the observed associations is possible. In order to better assess exogenous risk factors of ALS, a job exposure matrix (JEM) may have to be used, with a detailed exposure index to electric fields and magnetic fields [70]. Metals have been studied for a long time in order to understand pathogenic mechanisms underlying development of neurodegenerative disease better, and to date there are prospects of study for this topic [71].…”

Comments on “Maternal exposure to extremely low frequency magnetic fields: Association with time to pregnancy and foetal growth”

“…Similarly, expert assessment of occupational EMF exposure is notoriously difficult (Kheifets et al 2009;Savitz, 1995;Miller and Green, 2010), while the inference of personal EMF exposure from appliances based on self-reported information is also known to be subject to considerable error (Savitz, 1995). All these may have contributed to the work of Eskelinen et al being underpowered, as evidenced by the very wide confidence intervals of the effect estimates that they report.…”

“Dirty electricity”: what, where, and should we care?

“…Further complications in exposure estimation will be introduced as , even though some data suggest biological systems might be especially susceptible to non-linear 'resonant' frequency-amplitude combinations (Zhadin, 2001;Binhi and Savin, 2002), biological effects from HFVT might be caused by the intermittent nature of HFVT compared to the LF-RF frequency harmonic sine waves that carry the transients (Ivancsits et al, 2002;Mathur, 2008). These factors will most likely only further increase the potential for exposure misclassification in studies relating ''standard'' EMF exposure metrics to health effects (Kheifets et al, 2009;Schuz et al, 2009). …”