Hypertension linked to 2.5 times higher risk of epilepsy

• Researchers investigated the link between high blood pressure and epilepsy.
• They found that high blood pressure increases the risk of epilepsy by around 2.5 times but taking antihypertensive medications reduces this risk.
• They conclude that while high blood pressure is a risk factor for epilepsy, further research is needed to understand the underlying mechanisms of the link.After stroke and dementia, epilepsy is the third most frequent neurological illness that affects the elderly.Late-onset epilepsy has become increasingly common in the previous two decades, according to research. As the population ages, the number of persons suffering from epilepsy is projected to climb, and epilepsy will likely become a major public health issue.Despite this, the fundamental causes of epilepsy are unknown in 32–48% of casesTrusted Source. a little research According to Trusted Source, vascular risk factors may raise the likelihood of late-onset epilepsy. Other studies According to Trusted Source, vascular risk factors may be implicated.

   

  Understanding the role of vascular risk factors in late-onset epilepsy could help policymakers design public health measures and preventive strategies to curb and manage rates of the condition.Researchers from Boston University School of Medicine in the United States have undertook a study to look at the link between vascular risk factors and epilepsy development.

  They discovered that hypertension was linked to a nearly 2-fold increased incidence of late-onset epilepsy. This risk was much higher for people who did not use blood pressure medication to control it.

 

 

Data analysis

The researchers used data from the Framingham Heart Study (FHS), an ongoing, community-based study that began in     1948. Its Offspring Cohort tracks the health outcomes of 5,124 of the original participants’ children from health                 examinations every 4 years.

Altogether, the researchers used data from 2,986 people who attended their fifth examination between 1991 and 1995, were at least 45 years old during the period, and whose health records contained data on vascular risk factors.

The vascular risk factors collected included systolic and diastolic blood pressure. The researchers characterized high blood pressure as systolic blood pressure of 140 millimeters of mercury (mm Hg) and above, and diastolic blood pressure of 90 mm Hg and above, as well as the use of antihypertensive medications.

The researchers also screened for:

• diabetes
• cholesterol levels
• smoking status
• cardiovascular disease
• stroke
• body mass index (BMI)

To screen participants for epilepsy or seizure, the researchers used routine chart reviews for neurological conditions, self-reported seizures, International Classification of Diseases Ninth Revision (ICD-9)Trusted Source codes linked to epilepsy or seizures, and antiepileptic drug use.

The researchers also used brain imaging and electroencephalography (EEG), cardiac and other relevant data to ascertain cases of epilepsy.

Among the cohort, the research identified 55 examples of epilepsy, of which 26 were definite, 15 probable, and 14 suspected. Individuals were an average of 73.8 years old at the time of potential diagnosis.

The researchers found that hypertension had links to an almost 2-fold higher risk of epilepsy. However, the other risk factors had no links to epilepsy.

After excluding people taking antihypertensive medications, the researchers noted that high blood pressure had links to a 2.44-fold high risk of developing epilepsy.

They also found that every 10 mm Hg change in systolic blood pressure was associated with a 17% higher risk of developing epilepsy.

 

 

Underlying mechanisms

Several theories may explain the link between epilepsy and hypertension. One mechanism may be via the renin-angiotensin system (RAS)Trusted Source, which regulates blood pressure.

ResearchTrusted Source suggests that after repetitive seizures, rats have 2.6–8.2 times the components of RAS than mice without seizures. Antihypertensive drugs that lowered levels of RAS components delayed seizure onset and reduced seizure frequency.

However, more research is needed to understand how much this mechanism explains the link between epilepsy and hypertension, as other research suggests the system may have a limited effect.

According to the researchers, another possible underlying mechanism is small vessel disease (SVD)Trusted Source, a condition in which the walls of small arteries and capillaries are damaged and thus do not deliver sufficient oxygen-rich blood to various organs. In a recent study, scientists foundTrusted Source that the duration of high blood pressure is a strong predictor of SVD in later life.

The researchers add that SVD has links to temporal lobe epilepsy. Possible mechanisms include cortical microinfarcts, small lesions in cortical tissue, and the disruption of U fibersTrusted Source that may lead to excessive excitability and thus seizures. U fibers connect neighboring areas of the cerebral cortex.