Non-specific physical symptoms and electromagnetic field exposure in the general population: Can we get more specific? A systematic review

Objective: A systematic review of observational studies was performed to address the strength of evidence for an association between actual and perceived exposure to electromagnetic fields (EMF) and non-specific physical symptoms (NSPS) in the general population. To gain more insight into the magnitude of a possible association, meta-analyses were conducted. Methods: Literature databases Medline, Embase, SciSearch, Psychlnfo, Psyndex and Biosis and additional bibliographic sources such as reference sections of key publications were searched for the detection of studies published between January 2000 and April 2011. Results: Twenty-two studies met our inclusion criteria. Qualitative assessment of the epidemiological evidence showed either no association between symptoms and higher EMF exposure or contradictory results. To strengthen our conclusions, random effects meta-analyses were performed, which produced the following results for the association with actual EMF; for symptom severity: Headache odds ratio (OR) = 1.65; 95% confidence interval (CI) = 0.88-3.08, concentration problems OR = 1.28; 95% CI = 0.56-2.94, fatigue-related problems OR = 1.15; 95% CI = 0.59-2.27, dizziness-related problems OR = 1.38; 95% CI = 0.92-2.07. For symptom frequency: headache OR = 1.01; 95% CI =0.66-1.53, fatigue OR= 1.12; 95% CI = 0.60-2.07 and sleep problems OR= 1.18; 95% CI = 0.80-1.74. Associations between perceived exposure and NSPS were more consistently observed but a meta-analysis was not performed due to considerable heterogeneity between the studies. Conclusions: This systematic review and meta-analysis finds no evidence for a direct association between frequency and severity of NSPS and higher levels of EMF exposure. An association with perceived exposure seems to exist, but evidence is still limited because of differences in conceptualization and assessment methods. (C) 2011 Elsevier Ltd. All rights reserved.