Case-control study of occupational exposure to electric shocks and magnetic fields and mortality from amyotrophic lateral sclerosis in the US, 1991–1999

Abstract

We investigated the relationship between occupational exposure to electric shocks (ES) and magnetic fields (MF) and amyotrophic lateral sclerosis (ALS) using 1991-1999 US mortality data. For each of the 5886 included ALS deaths, 10 controls-matched on sex-, age-, year- and region-were selected from among other deaths. Usual occupation as reported on death certificates was linked to job-exposure matrices for ES and MF. Education and electric occupations were associated with moderately increased ALS risks (odds ratio (OR)=1.85, 95% confidence interval (CI)=1.67, 2.04; OR=1.23, 95% CI=1.04, 1.47, respectively). For ES, ALS mortality OR were 0.73 (95% CI=0.67, 0.79) for high and 0.90 (95% CI=0.84, 0.97) for medium exposure compared with low exposure. For MF, ALS ORs were 1.09 (95% CI=1.00, 1.19) for high and 1.09 (95% CI=0.96, 1.23) for medium exposure as compared with low exposure. For electric occupations, ALS ORs were insensitive to adjustments for ES, MF or both. Consistent with previous publications, an association between electric occupations and ALS was observed. Findings do not support occupational exposure to ES or MF as an explanation.

Amyotrophic Lateral Sclerosis and Occupational Exposures: A Systematic Literature Review and Meta-Analyses

“…Focusing only on the first aspect (vaporized metals), we used risk rates based on years at work with welding and the weighted RR was 0.95 (95% CI 0.70–1.29), (Figure 5) [22,23,27,32,40,48,51,54]. The heterogeneity was apparent and leaving out the big study by Feychting [22], it was reduced from 82% to 77%.…”

“…The exposures can be separated into electrical accidents/trauma and electromagnetic fields (EMF) per se. The level of EMF exposure was estimated through a job exposure matrix (JEM) established by occupational hygienists [22,31,32,33,39,40,41,44,47,54], and the weighted RR was 1.23 (95% CI 1.04–1.45), which is statistically significant (Figure 6). …”

“…When the focus is on electrical accidents/trauma, the exposure is based on job titles and years of work with electricity [22,23,26,31,34,39,45,46,51,54], resulting in the slightly elevated weighted RR = 1.16 (95% CI 1.00–1.35). Meta-regression showed that there was no statistically significant difference between the two types of exposure, p = 0.57, and the heterogeneity was almost the same.…”

“…Only studies [18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54] fulfilling good scientific standards (Armon class II or III) were used in our meta-analyses; see Table 1. Another 46 relevant publications [3,9,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,…”

Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease: an update of a Danish cohort study among utility workers

“…In a study published after the meta-analyses, Sorahan and Mohammed (2014) found no convincing evidence of a higher risk for motor neurone disease in a cohort of electricity supply workers in the UK. Three subsequent studies reporting on exposure to ELF-MF and risk of ALS including information on electrical shocks have found contradicting results: Vergara et al (2015) observed an association between electric occupations and risk of ALS, but no association to electric shocks or magnetic fields, while Huss et al (2015b) reported an association between magnetic fields and ALS, but no association to electric shocks and Fischer et al (2015) found no association between electric occupations and ALS, but a weak association between electric shocks and ALS.…”