Risk of cognitive impairment in relation to elevated exposure to electromagnetic fields.

Occupational exposure to power-frequency electromagnetic fields (PF-EMF) has been suspected of being associated with adverse neurological outcomes. We performed a case-control study to assess the relationship between exposure to PF-EMF and the risk of cognitive impairment, an indication of certain adverse neurological diseases such as Alzheimer's disease and dementia. Among 2198 elderly individuals aged 65 years or older, 290 persons with score-based cognitive impairment were compared with 580 sex-matched controls to assess the risk of cognitive impairment in relation to PF-EMF exposure. Participants who were former electrical workers or living within 100 meters of high-voltage transmission lines were considered to have higher exposure. Compared with background exposure, the risk was equal or close to unity for participants with higher exposure from a previous occupation (odds ratio [OR], 1.3; 95% confidence interval [CI], 0.7 to 2.3), higher residential exposure (OR, 0.9; 95% CI, 0.3 to 2.6), or higher exposure in both occupation and residential environments (OR, 1.0; 95% CI, 0.2 to 4.6). Our findings provide little support for the link between PF-EMF and cognitive impairment. Nevertheless, the study results do not preclude the possible association between PF-EMF and any specific neurodegenerative disease previously investigated.