Study type: Epidemiological study (observational study)

Occupational exposure to extremely low-frequency magnetic fields and the risk of ALS: A systematic review and meta-analysis epidem.

Published in: Bioelectromagnetics 2018; 39 (2): 156-163

Aim of study (acc. to author)

The association between occupational exposure to extremely low-frequency magnetic fields and the risk of amyotrophic lateral sclerosis (ALS) evaluated in a meta-analysis based on 20 studies.

Further details

Following studies were included in the pooled analysis: Davanipour et al. (1997), Deapen et al. (1986), Fang et al. (2009), Feychting et al. (2003), Fischer et al. (2015), Gunnarsson et al. (1991), Gunnarsson et al. (1992), Hakansson et al. (2003), Huss et al. (2015), Koeman et al. (2017), Noonan et al. (2002), Park et al. (2005), Parlett et al. (2011), Pedersen et al. (2017), Röösli et al. (2007), Savitz et al. (1988a), Savitz et al. (1988b), Sorahan et al. (2007) and Vergara et al. (2015). Additionally, the study by Buckley et al. (1983) was included in which the job title was given without explicit relation to electromagnetic fields, therefore it is not included in the EMF-Portal.

Endpoint/type of risk estimation

Type of risk estimation:

Exposure

Assessment

Population

Statistical analysis method:

Results (acc. to author)

Overall, studies reported a slightly increased risk of amyotrophic lateral sclerosis in those workers exposed to higher levels of extremely low frequency magnetic fields compared to lower levels (RR 1.14, CI 1.00-1.30) and for workers in electrical occupations (RR 1.41, CI 1.05-1.92), but with large heterogeneity between studies (I²>70%). Self-reported exposure or occupations determined from death certificates did not show increased risks. Highest-longest types of exposure translated into increased risks of amyotrophic lateral sclerosis if the studies had evaluated the whole occupational history (RR 1.89, CI 1.31-2.73, I² 0%), in contrast to evaluating only few points in time (e.g., from census records, RR 1.06, CI 0.75-1.57, I² 76%).
The authors concluded that an increased risk of amyotrophic lateral sclerosis was observed in workers occupationally exposed to extremely low frequency magnetic fields . Results of studies depended on the quality of the exposure assessment.

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