Where you grow old in the United States may change your odds of developing epilepsy.
A new study in JAMA Neurology has mapped where older Americans are most likely to be diagnosed with epilepsy and points to a broad “epilepsy belt” running through the South, from Louisiana and Mississippi through Eastern Texas and Central Oklahoma.
The work, led by researchers at Case Western Reserve University and Houston Methodist, focused on those 65 and older enrolled in traditional Medicare. This is the group that already faces the highest rate of new epilepsy diagnoses in the country, yet until now, no one had a detailed map of where those cases cluster and what local conditions might be linked to them.
The team analyzed Medicare claims in the United States between 2016 and 2019, focusing on those who received a new diagnosis of epilepsy in 2019 and had no epilepsy-related claims in the previous three years.
The rate of new epilepsy diagnoses that year ranged from 141 to 1,476 cases per 100,000, a more than tenfold gap. Hotspots concentrated in Louisiana, Eastern Texas, Central Oklahoma and parts of the Deep South. Lower-rate regions appeared in stretches of the Great Plains, Midwest and Northeast.
That pattern looks strikingly similar to the long-known “stroke belt” in the southeastern U.S., where stroke deaths have been high for decades. Stroke is the leading cause of epilepsy in older adults, so that overlap fits what neurologists already see in clinics.
Sleep, heat and everyday barriers
So, what were some of the reasons for the seizures?
Lack of sleep stood out at the top of the list. In regions where a large share of adults reported sleeping less than seven hours per night, older residents were much more likely to live in an epilepsy hotspot.
Sleep and epilepsy already have a tight relationship. Poor sleep can trigger seizures, and seizures can disrupt sleep. Sleep problems grow more common with age and are closely tied to poverty and chronic stress, which are more frequent in parts of the South and Appalachia that lit up on the map.
Heat was another strong signal. Areas with more days where the heat index topped 95 degrees Fahrenheit tended to show higher epilepsy rates among older adults. Hot days cluster in southern states and are becoming more frequent as the climate warms. Long stretches of extreme heat strain the heart and blood vessels, unsettle sleep, and discourage outdoor activity — a mix that can feed into stroke and other brain injuries that later lead to epilepsy.
Models also pointed toward physical inactivity, obesity, and a high share of uninsured adults as markers of high-incidence areas. Many of the regions with elevated epilepsy rates are areas where large numbers of people reach age 65 after decades with limited access to primary care and preventive services, often while living with untreated or poorly controlled chronic disease.
Regions with a larger share of residents working in agriculture or natural resources tended to have lower epilepsy rates, as did places with more recent arrivals from other states. The authors suggest that agricultural work may reflect more active daily lives and lower population density, and that high in-migration may point to healthier, more economically mobile populations. However, the researchers stress that those are informed guesses, not firm explanations.
What this does — and does not — tell people
The study sits at the “ecological” level, meaning it looks at places rather than individual medical charts. It cannot be said that a particular person developed epilepsy because their county is hot, sleep-deprived, and car-poor. Personal risk still depends on many things such as stroke history, head injuries, infections, tumors, genetics, and sometimes unknown causes.
Even so, the patterns matter. The map clearly shows that epilepsy in older adults is not spread evenly across the country and that it tends to cluster in communities facing a long list of social and environmental challenges. Those conditions are not fixed. Better sleep health programs, stronger stroke prevention, heat-wave planning that protects older residents, improvements in transportation, and earlier insurance coverage could all reduce the number of people with vulnerable brains and limited care.
For now, the authors argue that public health agencies and policymakers can use their map as a guide. High-burden regions in the South may warrant extra neurologists, more stroke and sleep clinics and outreach tailored to communities with poor access to transportation and care. Lower-rate areas in the Midwest and West are not off the hook either; they can still learn from the patterns and protect gains as the population ages.
For older Americans and their families, the message is simple but not hopeless: Epilepsy risk in late life is tied not just to biology but to the places people move through every day. Change the conditions in those places, and the map of epilepsy may change too.
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