A newly published nationwide study has, for the first time, produced a detailed map of where epilepsy most affects older adults in the United States, revealing apparent regional disparities tied to environmental and social conditions. Featured in JAMA Neurology, the research is the result of a collaboration between the Houston Methodist Research Institute and Case Western Reserve University. By analysing Medicare records, the team found that adults aged sixty-five and older experience significantly higher rates of epilepsy in parts of the American South—particularly Louisiana, Mississippi, East Texas and central Oklahoma—than in other regions.
Epilepsy affects an estimated 3.3 million people across the country, according to the U.S. Centres for Disease Control and Prevention. In 2019 alone, health care spending related to epilepsy and seizures reached $24.5 billion. Against this backdrop, the study offers a clearer picture of how the condition is distributed among older adults and raises important questions about the factors that contribute to those differences.
Lead investigator Weichuan Dong, PhD, of the Houston Methodist DeBakey Heart & Vascular Centre and Case Western Reserve University, explained that the research provides the first comprehensive national view of where epilepsy is most prevalent in later life. By applying advanced geospatial mapping to Medicare data, the team identified concentrated “hot spots” of high incidence across several southern states—a pattern they describe collectively as the “epilepsy belt”. Dong noted that understanding where the burden is highest is a crucial step in learning why these patterns exist and how communities might better target prevention and care.
The study also identified several influential social and environmental factors linked to increased epilepsy incidence. Among them were insufficient sleep, defined as fewer than seven hours per night; frequent exposure to extreme heat, measured as days with a heat index above ninety-five degrees; low levels of physical activity; lack of health insurance among younger adults, which may delay diagnosis until Medicare coverage begins; and limited access to a household vehicle. These conditions, often shaped by local socioeconomic realities, were more common in regions with the highest case concentrations.
Co-author Siran Koroukian, PhD, of Case Western Reserve University School of Medicine, emphasised the strong association between extreme heat and new-onset epilepsy in older adults. She suggested that the finding highlights the growing relevance of climate-related risks to public health planning, especially given the ageing U.S. population.
Researchers used geospatial machine-learning methods to analyse data from 4.8 million Medicare beneficiaries between 2016 and 2019, drawing from the Medicare Master Beneficiary Summary File and the Agency for Healthcare Research and Quality. Alaska and Hawaii were excluded because of incomplete data. The analysis revealed previously unseen national patterns, showing how neighbourhood-level factors—from sleep habits and heat exposure to health care access and transportation—shape neurological health outcomes in later life.
More information: Weichuan Dong et al, Incidence and Risk Factors of Epilepsy Among Older Adults in the US Medicare Population, JAMA Neurology. DOI: 10.1001/jamaneurol.2025.4347
Journal information: JAMA Neurology Provided by Houston Methodist
