April 30, 2020
Older US veterans who developed unprovoked seizures of unknown etiology had double the risk of developing dementia over several years of follow-up, according to a study published online in JAMA Neurology.
“While seizures are commonly thought to occur in late stages of dementia, these findings suggest unexplained seizures in older adults may be a first sign of neurodegenerative disease,” researchers wrote.
The study included 292,262 veterans, 97% of whom were male, with an average age of 73. During a 5-year baseline period, 2166 veterans developed unprovoked seizures of unknown etiology. Veterans who developed seizures were more likely to be younger, black, have lower income, and have higher prevalence of comorbidities, researchers reported.
Over an average 6 years of follow-up, the veterans with late-onset unprovoked seizures had a 2-fold risk of being diagnosed with dementia compared with veterans without seizures, according to the study. When researchers accounted for comorbidities, the effect size and significance of the increased risk were similar. When they added a 2-year lag between seizure onset and dementia diagnose to refute possible reverse causation, the effect sizes and significance remained similar.
“These findings emphasize the need for comprehensive research on late-onset seizures and dementia,” researchers wrote. “Considering the growing elderly population and high incidence of late-onset unprovoked seizures of unknown etiology, further studies may have important ramifications for dementia research and clinical practice.”
Keret O, Hoang TD, Xia F, Rosen HJ, Yaffe K. Association of Late-Onset Unprovoked Seizures of Unknown Etiology With the Risk of Developing Dementia in Older Veterans [published online ahead of print, 2020 Mar 9]. JAMA Neurol. 2020;e200187. doi:10.1001/jamaneurol.2020.0187