Abstracts

Rationale: Some seizures can be prevented by avoiding known triggers, such as stress and sleep deprivation. If exposure to air or noise pollution increases seizure risk, patients with epilepsy may be able to prevent seizures by avoiding these exposures.  Our objective was to systematically synthesize the evidence examining whether exposure to outdoor air and noise pollution is associated with seizure risk.

Methods: We searched EMBASE, MEDLINE, SCOPUS, Web of Science, BIOSIS Previews, LILACS, Proquest Dissertations and Theses, conference abstracts, the grey literature, and conducted forward and backward citation tracing in January 2022 using terms representing air and noise pollution and seizures. Observational and ecological studies were included if they examined the effect of outdoor air or noise pollution on the risk of unprovoked seizures in humans. The risk of bias will be assessed using the Risk of Bias Assessment Instrument for Systematic Reviews Informing WHO Global Air Quality Guidelines. The characteristics and findings of the included studies were summarized descriptively, and a meta-analysis will also be conducted.

Results: We screened the titles and abstracts of 4,982 citations, retrieving 47 articles for full-text screening, with ten included in the review. The studies were conducted in Asia (n=6), North America (n=2), South America (n=1), and Australia (n=1). One study estimated the effect of a period of higher air pollution relative to periods of typical air pollution and reported that it increased seizure risk. The other nine studies estimated the effect of one or more specific air pollutants, but only seven clearly reported the results of a multivariable analysis. The effect of PM10, SO2, and NO2 was reported in all seven studies, CO in six, and PM2.5 and O3 in five. PM2.5 and PM10 significantly increased seizure risk in one study, SO2 in two studies, and O3 in one. NO2 and CO significantly increased risk in three studies and decreased risk in another. None of the included studies estimated the effect of general or source-specific noise pollution.

Conclusions: Evidence suggesting that air pollution affects seizure risk is inconsistent, and research on the effect of noise pollution was not identified. Additional research is necessary to elucidate their effects.

Funding: Lawson Health Research Institute’s Internal Research Fund; Schulich School of Medicine & Dentistry’s Collaborative Research Seed Grant; Jack Cowin Endowed Chair in Epilepsy Research at Western University; Government of Ontario’s Ontario Graduate Scholarship; and Western University’s Western Graduate Research Scholarship