Epilepsy isn’t something we typically associate with particular geographic regions, but new research seems to suggest a connection has been overlooked, at least in the United States.

The work found that there are parts of the US where the rate of epilepsy is much higher than elsewhere. Researchers analyzed Medicare data from Americans age 65 and older nationwide. Older adults were more likely to be diagnosed with epilepsy if they lived in the Southeastern U.S., they found. And that suggests that the region could have risk factors that particularly contribute to the higher rate, whether because of the hotter climate or because there is greater disparity in medical care in general.

“Social and environmental conditions that are modifiable at the local level could contribute to the incidence of epilepsy in older adults, and that could help prevention efforts be tailored by location,” wrote the authors of the work published this month in JAMA Neurology.

The epilepsy fringe

Epilepsy is characterized by unusual electrical activity in the brain, which causes recurrent seizures. There are many different causes and different forms of epilepsy, but it is known that there are population groups that are more likely to suffer from it, including older adults.

Although previous studies have found that the prevalence of diagnosed epilepsy may differ between regions of the world and the US, the scientists who conducted this new study say they have drawn the first map showing how frequently epilepsy affects older Americans on a national level.

The researchers are from the Houston Methodist Research Institute in Texas and Case Western Reserve University in Ohio. They analyzed Medicare data from 2016 to 2019, focusing on cases of epilepsy diagnosed in 2019. That year there were 20,000 new diagnoses, and the incidence rate of epilepsy varied greatly between different regions of the US.

They found that the highest rates were in southeastern states such as Louisiana, Mississippi and Texas. The researchers also identified several factors that appeared to correlate with epilepsy in this “epilepsy band,” as they called it. Rates of insufficient sleep were higher in Louisiana, Alabama and Georgia, for example. The southern states with the most days of extreme heat in the year and states like Texas and Florida with higher rates of people without health insurance (young people without insurance are the most likely to not go to the doctor’s appointment, and that could delay the diagnosis).
Although some of these factors are understood to clearly increase the risk of suffering from epilepsy, such as lack of sleep, there are potential causes that have not received as much attention.

“This is the first study to document a strong relationship between extreme heat and the incidence of epilepsy in older adults in the US, highlighting the importance of climate change on how prepared we are for emergencies, especially as longevity is increasing,” said Siran Koroukian, a professor in the Department of Population Sciences and Quantitative Health at Case Western Reserve University School of Medicine.

What’s notable is that this is the same region of the US with higher rates of cardiovascular accidents, which is why researchers call the region the “cardiovascular accident belt.” Since cardiovascular events are a major risk factor for epilepsy, this is also likely to contribute to new cases.

Areas to improve

There are an estimated 3 million American adults living with epilepsy. Although the condition today is not curable in most cases, it can be effectively treated with medication, surgery, and management of potential triggers.

The researchers hope their findings will contribute to improved epilepsy prevention and mitigation efforts in various public health interventions in areas of the country where risk factors are highest.

“That could include improving sleep health, heat resilience, and reducing barriers related to transportation and health care,” they indicate in their work.

This article was translated from Gizmodo US by Lucas Handley. Here you can find the original version.