Ambient air pollution breathed daily, specifically related to greater concentrations of carbon monoxide (CO), may be associated with an increased risk for epileptic seizures. It may also be more significantly associated with seizures in which symptoms are not noticeable. These are the findings of a study published in Epilepsia.
Previous studies have shown the threat of air pollution to the heart and the lungs. Air pollution has been associated with a higher risk for neurological disorders, including stroke, migraine, cognitive deficit, neurodegenerative diseases, and psychiatric disorders, the researchers explained. With air pollution, the brain can be exposed to chemicals that affect brain metabolism and neuronal excitability which could incite seizures. However, the effect of air pollution on the occurrence of epileptic seizures is unknown.
The objective of the current study was to examine the relationship between air pollutant exposure and epileptic seizures.
The researchers conducted a retrospective review of the Neuro Vista dataset in Australia from 2010 to 2012 of 15 participants with refractory focal epilepsy presenting 3273 seizures recorded with intracranial electroencephalography (iEEG), and a review of the Seer App seizure diary dataset in Australia from 2018 to 2021 of 34 participants with epilepsy presenting 3419 self-reported seizures recorded with a mobile application.
Data from the Environment Protection Authority provided local information concerning average pollution measures of CO, nitrogen dioxide (NO2), ozone (O3), particulate matter equal to or less than 10 μm in diameter (PM10), and sulfur dioxide (SO2) on the days of seizures. Hourly observations that were included in the daily mean data.
The study findings revealed all daily concentrations of CO and SO2, and at least 95% of daily concentrations of NO2, O3, and PM10 were within Australian air quality standards.
For pollutants NO2, O3, PM10, and SO2, there was no meaningful association with the risk for clinical or subclinical epileptic seizures. CO concentrations showed an increased risk for clinical epileptic seizures of 4% (relative risk [RR]: 1.04; 95% CI, 1.01-1.07) for an interquartile range (IQR) increase of CO concentrations (0.13 parts per million). The risk was worse for females exposed to elevated levels of CO (RR: 1.05; 95% CI, 1.01-1.08) and elevated levels of NO2 (RR: 1.09; 95% CI, 1.01-1.16). For subclinical seizures, a greater association was also recorded with CO (RR: 1.20; 95% CI, 1.12-1.28).
Study limitations included the potential inaccuracy of self-reported seizures, measurement and estimation bias of ambient pollution, and underpowered sampling.
Researchers concluded that an increased risk for epileptic seizures, notably subclinical seizures, could be associated with daily exposure to increased CO air pollution.
Implications of this association are important for public health.
“Our findings suggest that CO exposure could be explored as a potential new feature for seizure risk forecasting, which may be used to reduce the uncertainty of seizures and guide epilepsy management. Furthermore, our study could also drive new potential approaches to reduce seizure risks by managing behavior when pollutant levels are high or using air filtration systems to reduce exposure to high CO.”
Chen Z, Yu W, Xu R, et al. Ambient air pollution and epileptic seizures: A panel study in Australia. Epilepsia. Published online April 8, 2022. doi:10.1111/epi.17253