No association worth making between EM fields and degenerative CNS disease

Journal of Occupational & Environmental Medicine: February 2013 - Volume 55 - Issue 2 - p 135–146 doi: 10.1097/JOM.0b013e31827f37f8

Occupational Exposure to Extremely Low-Frequency Magnetic Fields and Neurodegenerative Disease: A Meta-Analysis

Vergara, Ximena PhD; Kheifets, Leeka PhD; Greenland, Sander DrPH; Oksuzyan, Sona MD; Cho, Yong-Sung PhD; Mezei, Gabor MD, PhD

Abstract

Objective: Previous studies reported associations of occupational electric and magnetic fields (MF) with neurodegenerative diseases (NDDs). Results differ between studies using proxy exposure based on occupational titles and estimated MF levels. We conducted a meta-analysis of occupational MF NDD, primarily Alzheimer disease (AD), and motor neuron diseases (MNDs) studies.

Methods: We identified 42 peer-reviewed publications and focused our analysis on study characteristics, exposure metrics, and publication bias.

Results: We found weak associations for occupational MF exposure proxies with AD and MND. Motor neuron disease risk was associated with occupational titles, whereas AD risk was associated with estimated MF levels. Results varied in study design, with dissimilar variation across diseases.

Conclusions: Our results do not support MF as the explanation for observed associations between occupational titles and MND. Disease misclassification, particularly for AD, and imprecise exposure assessment affected most studies.