Abstracts

Rationale: Physical exercise has a positive impact on brain structure and function and can protect the brain from neurodegenerative disorders. Studies have shown positive effects of exercise on seizure frequency and severity in patients with epilepsy. Although exercise have positive outcomes for patients who already have epilepsy, possible preventative effects of exercise on seizure susceptibility and development of epilepsy in humans is unknown. However, results from experimental animal models are encouraging where exercise influences epileptogenesis in a positive manner. There is a clear need for longitudinal prospective studies with an objective measure of physical fitness in humans. Therefore, we performed a large, prospective cohort study of men at age 18 and followed them for up to 40 years. The aim was to determine whether cardiovascular fitness measured at age 18 was associated with risk of developing epilepsy later in life. We also wanted to investigate if presence of a prior traumatic head injury influenced the observed associations. Methods: Population-based, prospective cohort study of Swedish male conscripts (n=1,173,079) born in 1950-1987, who were followed for up to 40 years. Objective data of cardiovascular fitness, as measured by the cycle ergonometric test, were collected during conscription exams and linked with national hospital discharge registers and other national databases to calculate future risk of epilepsy. We used Cox proportional hazards models to assess the influence of the cardiovascular performance at age 18 on the occurrence of epilepsy later in life. Results: The numbers of individuals who received inpatient treatment for epilepsy during the observation period was 6,796. In fully adjusted models, low cardiovascular fitness at age 18 was associated with increased risk for future epilepsy (HR 1.79, 95%, CI 1.57-2.03). In a full-brother model, thus controlling for familial influences, low cardiovascular fitness remained a significant predictor (HR 1.66, 95%, CI 1.39-1.98). The associations between cardiovascular fitness and later epilepsy remained in individuals who had a head injury prior to the epilepsy diagnosis (HR 1.88, 95%, CI 1.41-2.51). Conclusions: Low cardiovascular fitness at age 18 increases the risk for epilepsy later in life. The associations of cardiovascular fitness and epilepsy were still significant after controlling for a number of possible confounders including familial factors. This is a unique study with a large and prospective cohort, long observation period and objective measures of physical performance that correlates well with and extends other studies reporting positive effects of exercise on patients already diagnosed with epilepsy. We propose that physical activity may act as a positive disease-modifying behavior for the development of epilepsy.