Occupational exposure to extremely low-frequency magnetic fields and neurodegenerative disease: a meta-analysis.

Abstract

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