Epilepsy and dementia are linked because patients with epilepsy have a two-fold risk of developing dementia and patients with dementia are at increased risk of epilepsy, according to study results published in Neurology.
Recent studies have suggested a bidirectional relationship between dementia and epilepsy, with evidence of a 2- to 10-fold increased risk of seizures in patients with dementia. Another study reported an increased risk of dementia in patients with epilepsy.
The aim of the current study was to use data from the Framingham Heart Study to determine the risk of epilepsy in patients with predominant dementia and the risk of dementia in patients with predominant epilepsy.
The study researchers used a nested case-control design to assess epilepsy after a diagnosis of dementia. Each patient with dementia was compared to 3 controls without dementia from the cohorts of the original and progeny Framingham heart study. The study researchers used a similar procedure to assess dementia after a diagnosis of epilepsy. In a secondary analysis, they assessed the role of education level and allelic status of apolipoprotein ε4 (APOE4) in changing the relationship between epilepsy and dementia.
The study included 4906 patients with available data on epilepsy and dementia and a follow-up of at least 65 years. Of these, 888 patients were diagnosed with dementia and 90 with epilepsy.
Appropriate controls were available for each of 660 patients with dementia. The control group comprised 1980 participants without dementia. During the follow-up visit there were 58 patients with epilepsy, including 19 (2.9%) patients with predominant dementia and 39 (2.0%) patients with dementia-free dementia (hazard ratio) [HR]1.82; 95% CI, 1.05-3.16; P = 0.034). The results were similar after adjusting for education and APOE4.
Among the 43 patients with epilepsy and 129 epilepsy-free controls, 51 patients with incident-related dementia were at follow-up, including 18 patients (41.9%) among those with predominant epilepsy and 33 patients (25.6%) among the epilepsy-free controls (HR 1.99; 95% CI 1.11-3.57; P = 0.021). The results were similar after adjusting for education and APOE4.
In participants with post-high school education, the prevalence of epilepsy was almost five times the risk of developing dementia compared to patients in the control group (HR 4.67; 95% CI 1.82-12.01; P. = 0.001) connected the same training.
The study had several limitations, including the confusing presence of a clinical stroke, the inability to consider the potential effect of anti-seizure drugs on the diagnosis of dementia, a lack of data on seizure frequency, and the inclusion of a mainly Caucasian population, which limited the generalizability of the results .
“There is a two-way relationship between epilepsy and dementia, with both diseases having an almost twofold risk of developing the other compared to controls,” the study’s researchers concluded.
Stefanidou M., Beiser AS, Himali JJ, et al. The bidirectional relationship between epilepsy and dementia. The Framingham Heart Study. Neurology. Published online on October 23, 2020. doi: 10.1212 / WNL.0000000000011077