Study Uncovers ‘Epilepsy Belt’ in the Southern United States

A groundbreaking study has identified significant regional disparities in epilepsy rates among older adults in the United States. Conducted collaboratively by researchers from the Houston Methodist Research Institute and Case Western Reserve University, the findings were published in JAMA Neurology. The research highlights areas in the South, particularly Louisiana, Mississippi, East Texas, and central Oklahoma, as having notably higher incidence rates of epilepsy among adults aged 65 and older.

Currently, epilepsy affects approximately 3.3 million individuals across the United States, as reported by the U.S. Centers for Disease Control and Prevention. In 2019, health care expenditures related to epilepsy and seizures reached $24.5 billion. This new study provides essential insights into how epilepsy manifests in older populations, revealing geographic patterns that could lead to enhanced preventive measures and care strategies.

Lead investigator Weichuan Dong, Ph.D., who serves as an assistant professor at the Houston Methodist DeBakey Heart & Vascular Center and is an adjunct assistant professor at Case Western Reserve University, emphasized the importance of this research. “Until now, we didn’t have a national picture of where epilepsy affects older adults the most,” he stated. “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 analyzed data from 4.8 million Medicare beneficiaries between 2016 and 2019, utilizing the U.S. Medicare Master Beneficiary Summary File and the Agency for Healthcare Research and Quality. Notably, Alaska and Hawaii were excluded from the analysis due to incomplete data regarding social and environmental determinants of health.

Researchers identified several key factors linked to increased epilepsy rates. These include insufficient sleep, with fewer than seven hours per night, exposure to extreme heat conditions (with many days exceeding a heat index of 95 degrees Fahrenheit), a lack of physical activity, absence of health insurance among younger adults, and limited access to household vehicles. These factors, often influenced by local environments and socioeconomic conditions, were predominantly found in regions with elevated epilepsy rates.

Siran Koroukian, Ph.D., a professor in the Department of Population and Quantitative Health Sciences at Case Western Reserve University School of Medicine, remarked on the study’s findings. “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.”

The research reveals patterns that were previously obscured in national data, illustrating how neighborhood sleep habits, heat exposure, healthcare access, and vehicle availability can influence health outcomes. Other significant predictors of epilepsy incidence included obesity prevalence and the availability of primary care physicians.

This study represents a critical step in understanding epilepsy’s impact on older adults and the environmental and social factors contributing to its prevalence. The insights gained could inform targeted interventions and health policies aimed at reducing the burden of epilepsy in vulnerable populations.

For further reading, refer to the full study: Weichuan Dong et al, Incidence and Risk Factors of Epilepsy Among Older Adults in the US Medicare Population, JAMA Neurology (2025). DOI: 10.1001/jamaneurol.2025.4347.