Risk factors for late-onset epilepsy among people with cognitive decline identified

Factors such as APOE4 allele, dementia onset before age 60 years, Alzheimer’s disease (AD) dementia subtype, worse cognition, stroke/transient ischaemic attack (TIA), and Parkinson’s disease (PD) all contribute to a heightened risk of late-onset epilepsy in people with cognitive decline, as reported in a study.

The study included 14,685 participants (mean age 73.8 years, 50 percent female) from 39 Alzheimer’s Disease Research Centers in the US. These participants had cognitive decline, were free of epilepsy at baseline, had attended at least two follow-up visits, and were at least 60 years at the most recent follow-up.

Late-onset epilepsy, the primary outcome, was defined as seizures starting at or after 60 years of age. Multivariable Cox regression analysis was performed to examine the association between multiple factors and the outcome.

During the follow-up, late-onset epilepsy occurred in 221 participants (1.5 percent). Multivariable Cox regression analysis showed that the risk of late-onset epilepsy was significantly associated with the following variables: APOE4 allele (adjusted hazard ratio [aHR], 1.39, 95 percent confidence interval [CI], 1.04–1.86; p=0.03), dementia onset before age 60 years (aHR, 2.46, 95 percent CI, 1.53–3.95; p<0.001), worse cognition (aHR, 2.35, 95 percent CI, 1.97–2.79; p<0.001), AD dementia subtype (aHR, 1.68, 95 percent CI, 1.13–2.49; p=0.01), stroke/TIA (aHR, 2.03, 95 percent CI, 1.37–3.01; p<0.001), and PD (aHR, 2.53, 95 percent CI, 1.08–5.95; p=0.03).

Similar results were obtained in a sensitivity analysis wherein late-onset epilepsy was defined as seizures starting after age 65 years.

The risk factors identified in the study may be considered for routine screening with an electroencephalogram for early identification of late-onset epilepsy, according to the investigators.