A first-of-its-kind nationwide study has mapped epilepsy incidence rates among older adults in the United States and identified key social and environmental factors associated with the neurological condition. Published recently in JAMA Neurology, the study is a collaborative effort between researchers at Houston Methodist Research Institute and Case Western Reserve University. The analysis revealed that epilepsy cases among adults aged 65 and older were significantly higher in parts of the South—including Louisiana, Mississippi, East Texas and central Oklahoma—compared to other regions.
Epilepsy affects an estimated 3.3 million people in the United States, according to the U.S. Centers for Disease Control and Prevention. In 2019, health care spending on epilepsy and seizures reached $24.5 billion.
Against this backdrop, the study's lead investigator, Weichuan Dong, Ph.D., assistant professor at the Houston Methodist DeBakey Heart & Vascular Center and adjunct assistant professor at Case Western Reserve University, said the research offers critical insight into how epilepsy impacts older adults nationwide—revealing geographic patterns that could reshape how communities approach prevention and care for this neurological condition.
"Until now, we didn't have a national picture of where epilepsy affects older adults the most," Dong said. "By applying advanced geospatial mapping to Medicare data, we revealed striking clusters of high epilepsy rates across parts of the South — what we call the 'epilepsy belt.' Understanding where the burden lies is the first step toward uncovering why and helping communities reduce risk."
The study also found that the most influential factors linked to higher epilepsy incidence included insufficient sleep (fewer than seven hours per night), extreme heat (more days with heat index above 95 degrees), lack of physical activity, lack of health insurance among younger adults (suggesting delayed diagnosis until Medicare eligibility) and limited access to a household vehicle. These conditions, often shaped by local environments and socioeconomic status, were more prevalent in regions with the highest epilepsy rates.
"This is the first study documenting such a strong association between extreme heat and incident epilepsy in older adults across the U.S., highlighting the importance of climate change in emergency preparedness, especially given the graying of the population," said Siran Koroukian, Ph.D., professor in the Department of Population and Quantitative Health Sciences at Case Western Reserve University School of Medicine.
Using advanced geospatial machine learning algorithms, researchers analyzed data from 4.8 million Medicare beneficiaries between 2016 and 2019. Data sources included the U.S. Medicare Master Beneficiary Summary File and the Agency for Healthcare Research and Quality. Alaska and Hawaii were excluded due to incomplete data from the Social and Environmental Determinants of Health report.
The study uncovered patterns previously invisible in national data, showing how factors like neighborhood sleep habits, heat exposure, health care access and household vehicle access can shape health outcomes. Other strong predictors included obesity prevalence and availability of primary care physicians.
Collaborators on the study included Alex Cabulong, Long Vu, Hannah Fein, Nicolas Schiltz and Martha Sajatovic from Case Western Reserve University; Sadeer Al-Kindi from Houston Methodist Heart and Vascular Center; David Warner from University of Alabama at Birmingham and Bowling Green State University; and Gena Ghearing from Mount Sinai Health System.
This work was supported in part by a grant from the Centers for Disease Control and Prevention of the U.S. Department of Health and Human Services (U48 DP006404-03S7) and the Center for Family and Demographic Research, Bowling Green State University (P2CHD050959). Additional support was provided by the Health Systems Management Center Leadership Fund from Case Western Reserve University.
