Hypertension, diabetes, and smoking in midlife are potentially modifiable risk factors for late-onset epilepsy, according to a study that also found an increased risk with the apolipoprotein E4 (APOE4) genotype and in black individuals.
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Emily L. Johnson, MD, of Johns Hopkins University, Baltimore, and her coauthors analyzed data from 10,420 participants in the Atherosclerosis Risk in Communities prospective cohort study and found 596 who developed late-onset epilepsy (LOE), defined as recurrent unprovoked seizures starting at 60 years or older.
The study, published online July 23 in JAMA Neurology, showed that individuals with hypertension at baseline had a 30% higher risk of LOE, those who smoked had a 9% higher risk, and those with diabetes had a 45% higher risk. However, the increased risk associated with smoking was evident only in women, who had a 27% higher risk.
Participants with incident stroke had a 3.38-fold higher risk of LOE, and those with dementia had a 2.56-fold higher risk, Dr. Johnson and her colleagues reported.
“The association of LOE with vascular and lifestyle risk factors persisted after participants with diagnosis of clinical stroke or dementia were included or censored, suggesting that these risk factors may contribute to LOE even in the absence of dementia or clinical stroke,” the investigators wrote.
However, higher levels of physical activity decreased the risk by 10%, and moderate alcohol consumption – defined as 1-7 standard drinks per week – was associated with a 28% reduction.
Race and geographic location both influenced the risk of LOE; black participants showed a 66% higher risk, compared with whites, and black participants in Mississippi and North Carolina had a higher risk than did North Carolina white participants. The highest risk of LOE was seen in black participants with diabetes.
“The reasons for the different incidences of LOE by race/ethnicity may be owing to differing effects of comorbidities, such as diabetes, for which we found a significantly higher effect in black individuals than in white individuals,” the authors wrote.
Individuals who had one APOE4 allele showed a 46% higher risk, and those with two alleles showed a 2.57-fold higher risk.
“The APOE4 genotype is the major genetic risk factor for Alzheimer’s disease, which is associated with epilepsy; however, no prior association between APOE4 and LOE has previously been shown,” the authors reported.
The researchers noted that their findings suggested that lifestyle modifications earlier in life could mitigate some of the risk factors associated with LOE, and could also help identify patients at higher risk for the disease.
No funding was declared. One author declared consultancy and investigator positions with private industry.
SOURCE: Johnson E et al. JAMA Neurol, 2018 July 23. doi: 10.1001/jamaneurol.2018.1935.