Association of road traffic noise with the risk of new-onset epilepsy

The association of environmental noise with new-onset epilepsy has not yet been explored. Therefore, the study's objective was to assess whether long-term road traffic noise exposure is associated with the risk of new-onset epilepsy among adult residents of Toronto, Canada.

We conducted a nested case-control study using linked health administrative and environmental data. We included adult residents of Toronto as of January 1, 2010, with no history of seizures or epilepsy. Cases were those who developed epilepsy before December 31, 2016, and were each matched with up to five controls. We measured exposure to road traffic noise using three-year averages of the nighttime average (LA_{eq, 8 hr}), daytime average (LA_{eq, 16 hr}), and the 24-hour average (LA_{eq, 24 hr}) road traffic noise levels at participants' postal code of residence. We estimated the associations of these three-year noise averages with the risk of new-onset epilepsy using conditional logistic regression models.

We included 4,608 cases and 20,765 controls; 46.3 % were female and the mean age was 48.3 (± 17.4) years. The incidence rate ratios associated with a 10-dB increase in LA_{eq, 8 hr} was 1.043 (95 % CI: 0.994, 1.095), 0.999 (95 % CI: 0.946, 1.054) for LA_{eq, 16 hr}, and 1.031 (95 % CI: 0.980, 1.086) for LA_{eq, 24 hr}.

Although not statistically significant, these results point to a potential association between long-term exposure to road traffic noise, particularly average levels at night, and the risk of new-onset epilepsy. Future research should continue to explore this potential association.