Association between Extremely Low-Frequency Electromagnetic Fields Occupations and Amyotrophic Lateral Sclerosis: A Meta-Analysis

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Objectives

To estimate the relationship between exposure to extremely low-frequency electromagnetic fields (ELF-EMF) and the risk of amyotrophic lateral sclerosis (ALS) by a meta-analysis.

Methods

Through searching PubMed databases (or manual searching) up to April 2012 using the following keywords: “occupational exposure”, “electromagnetic fields” and “amyotrophic lateral sclerosis” or “motor neuron disease”, seventeen studies were identified as eligible for this meta-analysis. The associations between ELF-EMF exposure and the ALS risk were estimated based on study design (case-control or cohort study), and ELF-EMF exposure level assessment (job title or job-exposure matrix). The heterogeneity across the studies was tested, as was publication bias.

Results

Occupational exposure to ELF-EMF was significantly associated with increased risk of ALS in pooled studies (RR = 1.29, 95%CI = 1.02–1.62), and case-control studies (OR = 1.39, 95%CI = 1.05–1.84), but not cohort studies (RR = 1.16, 95% CI = 0.80–1.69). In sub-analyses, similar significant associations were found when the exposure level was defined by the job title, but not the job-exposure matrix. In addition, significant associations between occupational exposure to ELF-EMF and increased risk of ALS were found in studies of subjects who were clinically diagnosed but not those based on the death certificate. Moderate heterogeneity was observed in all analyses.

Conclusions

Our data suggest a slight but significant ALS risk increase among those with job titles related to relatively high levels of ELF-EMF exposure. Since the magnitude of estimated RR was relatively small, we cannot deny the possibility of potential biases at work. Electrical shocks or other unidentified variables associated with electrical occupations, rather than magnetic-field exposure, may be responsible for the observed associations with ALS.

Related collections

Most cited references 40

Record: found
Abstract: found
Article: found

Is Open Access

Amyotrophic lateral sclerosis

Lokesh C Wijesekera, P. Leigh (2009)

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive muscular paralysis reflecting degeneration of motor neurones in the primary motor cortex, corticospinal tracts, brainstem and spinal cord. Incidence (average 1.89 per 100,000/year) and prevalence (average 5.2 per100,000) are relatively uniform in Western countries, although foci of higher frequency occur in the Western Pacific. The mean age of onset for sporadic ALS is about 60 years. Overall, there is a slight male prevalence (M:F ratio~1.5:1). Approximately two thirds of patients with typical ALS have a spinal form of the disease (limb onset) and present with symptoms related to focal muscle weakness and wasting, where the symptoms may start either distally or proximally in the upper and lower limbs. Gradually, spasticity may develop in the weakened atrophic limbs, affecting manual dexterity and gait. Patients with bulbar onset ALS usually present with dysarthria and dysphagia for solid or liquids, and limbs symptoms can develop almost simultaneously with bulbar symptoms, and in the vast majority of cases will occur within 1–2 years. Paralysis is progressive and leads to death due to respiratory failure within 2–3 years for bulbar onset cases and 3–5 years for limb onset ALS cases. Most ALS cases are sporadic but 5–10% of cases are familial, and of these 20% have a mutation of the SOD1 gene and about 2–5% have mutations of the TARDBP (TDP-43) gene. Two percent of apparently sporadic patients have SOD1 mutations, and TARDBP mutations also occur in sporadic cases. The diagnosis is based on clinical history, examination, electromyography, and exclusion of 'ALS-mimics' (e.g. cervical spondylotic myelopathies, multifocal motor neuropathy, Kennedy's disease) by appropriate investigations. The pathological hallmarks comprise loss of motor neurones with intraneuronal ubiquitin-immunoreactive inclusions in upper motor neurones and TDP-43 immunoreactive inclusions in degenerating lower motor neurones. Signs of upper motor neurone and lower motor neurone damage not explained by any other disease process are suggestive of ALS. The management of ALS is supportive, palliative, and multidisciplinary. Non-invasive ventilation prolongs survival and improves quality of life. Riluzole is the only drug that has been shown to extend survival.

0 comments Cited 300 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

The epidemiology of motor neuron diseases: a review of recent studies.

Paul Worms (2001)

As the incidence and mortality rates of motor neuron diseases (MNDs) have been reported to increase steadily over the 1950s-1980s decades, we compared the results of the most recent studies (1990s decade) with the ones reported for those earlier periods. The relevant literature was retrieved on a keyword basis from online medical and official death statistics databases. Fifteen European and North American studies were analyzed, for comparison with the results reported in review papers. The 1990s incidence and mortality rates of MND average at 1.89 per 100,000/year and 1.91 per 100,000/year, respectively, thus yielding increases of 46% and 57% over the 1960s-1970s decades, respectively. This increase appears mainly due to Southern Europe countries, to female gender and to patients aged 75 years and over.Thus, the results of this analysis (i) confirm that the incidence of, and mortality from, MNDs continued to increase during the 1990s and, (ii) suggest that this increase could be partly due to increased life expectancy. Other factors might also contribute, such as better diagnosis since El Escorial criteria, and better accuracy of death certificate collection.However, a real increase in the incidence of MNDs, possibly related to environmental factors, cannot be excluded.

0 comments Cited 56 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Potential occupational risks for neurodegenerative diseases.

Stephen Bondy, Woolf Walker, Kyung Park … (2005)

Associations between occupations and neurodegenerative diseases (NDD) may be discernable in death certificate data. Hypotheses generated from 1982 to 1991 study were tested in data from 22 states for the years 1992-1998. Specific occupations and exposures to pesticides, solvents, oxidative stressors, magnetic fields, and welding fumes were evaluated. About one third (26/87) of the occupations hypothesized with neurodegenerative associations had statistically significant elevated mortality odds ratios (MOR) for the same outcome. Occupations with the largest MORs were (a) for presenile dementia (PSD)-dentists, graders/sorters (non-agricultural), and clergy; (b) for Alzheimer's disease (AD)-bank tellers, clergy, aircraft mechanics, and hairdressers; (c) for Parkinson's disease (PD)-biological scientists, clergy, religious workers, and post-secondary teachers; and (d) for motor neuron disease (MND)-veterinarians, hairdressers, and graders and sorters (non-agricultural). Teachers had significantly elevated MORs for all four diseases, and hairdressers for three of the four. Non-horticultural farmers below age 65 had elevated PD (MOR = 2.23, 95% CI = 1.47-3.26), PSD (MOR = 2.22, 95% CI = 1.10-4.05), and AD (MOR = 1.76, 95% CI = 1.04-2.81). Sixty hertz magnetic fields exhibited significant exposure-response for AD and, below age 65, for PD (MOR = 1.87, 95% CI = 1.14-2.98) and MND (MOR = 1.63, 95% CI = 1.10-2.39). Welding had elevated PD mortality below age 65 (MOR = 1.77, 95% CI = 1.08-2.75). Support was observed for hypothesized excess neurodegenerative disease associated with a variety of occupations, 60 Hz magnetic fields and welding. Published 2005 Wiley-Liss, Inc.

0 comments Cited 47 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Suminori Akiba: Role: Editor

Journal

Journal ID (nlm-ta): PLoS One

Journal ID (iso-abbrev): PLoS ONE

Journal ID (publisher-id): plos

Journal ID (pmc): plosone

Title: PLoS ONE

Publisher: Public Library of Science (San Francisco, USA )

ISSN (Electronic): 1932-6203

Publication date Collection: 2012

Publication date (Electronic): 26 November 2012

Volume: 7

Issue: 11

Electronic Location Identifier: e48354

Affiliations

[1 ]Bioelectromagnetics Laboratory, School of Public Health, Zhejiang University School of Medicine, Hangzhou, China

[2 ]Department of Epidemiology and Health Statistics, School of Public Health, Zhejiang University School of Medicine, Hangzhou, China

Kagoshima University Graduate School of Medical and Dental Sciences, Japan

Author notes

* E-mail: yunxianyu@ 123456gmail.com (YY); zpxu@ 123456zju.edu.cn (ZX)

Competing Interests: The authors have declared that no competing interests exist.

Conceived and designed the experiments: HZ ZX. Performed the experiments: HZ CC YY. Analyzed the data: GC YY. Contributed reagents/materials/analysis tools: HZ ZX. Wrote the paper: HZ GC.

Article

Publisher ID: PONE-D-12-16370

DOI: 10.1371/journal.pone.0048354

PMC ID: 3506624

PubMed ID: 23189129

SO-VID: 2c57936c-9789-4b90-b976-9c67d6330729

License:

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

History

Date received : 6 June 2012

Date accepted : 24 September 2012

Page count

Pages: 7

Funding

This work is supported by grants from the Ministry of Science and Technology (2011CB503702 and 2011CB503706), and the Fundamental Research Funds for the Central Universities (2012QNA7019 and 2012FZA7019). ZX was sponsored by the Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Association between Extremely Low-Frequency Electromagnetic Fields Occupations and Amyotrophic Lateral Sclerosis: A Meta-Analysis

Read this article at

Abstract

Objectives

Methods

Results

Conclusions

Related collections

PLOS Climate

Most cited references 40

Amyotrophic lateral sclerosis

The epidemiology of motor neuron diseases: a review of recent studies.

Potential occupational risks for neurodegenerative diseases.

Author and article information

Contributors

Journal

Affiliations

Author notes

Article

History

Page count

Funding

Categories

Comments

Comment on this article

Similar content 271

Cited by 21

Most referenced authors 601