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Researchers say many people are unaware they have risk factors that increase the likelihood of a stroke. Westend61/Getty Images
  • Researchers are reporting that two-thirds of people who’ve had acute ischemic strokes were unaware they had undiagnosed risk factors such as hypertension or high cholesterol.
  • Experts encourage people to schedule medical examinations that can determine if they are have one of these risk factors.
  • They also say you can reduce the risk of stroke and other conditions by eating healthy, exercising regularly, and not smoking.

Stroke is called a “silent killer” and researchers in a new study conclude that ignorance isn’t bliss when it comes to stroke patients.

Most people who’ve had acute ischemic strokes without prior symptoms had undetected health conditions that put them at risk of stroke, the researchers from Switzerland reported at the European Academy of Neurology Congress 2022.

Their findings haven’t been peer-reviewed or published yet

In their study, the researchers looked at the health records of 4,354 stroke patients who had no previously diagnosed risk factors. They found that 67 percent of them had at least one previously undiagnosed major risk factor (UMRF) for stroke.

The most common vascular UMRF was an imbalance of blood fats such as high cholesterol or raised levels of triglycerides (61 percent of patients), followed by high blood pressure (23 percent). One in 10 patients (10 percent) had atrial fibrillation, a condition that causes a fast and often irregular heartbeat. About 5 percent had diabetes.

Dr. André Rêgo. the lead study author and a researcher at Centre Vaudois, Lausanne, in Switzerland, said that clinical information has been “scarce” about the frequency, patient profile, and stroke mechanisms among stroke patients with previously undiagnosed major vascular risk factors.

“Our findings underline the importance of testing and treating blood fat imbalances such as high cholesterol and triglyceride levels, as well as blood pressure and identifying and treating those with atrial fibrillation and type 2 diabetes”, Rêgo said in a press release.

Medical experts told Healthline that risk factors for stroke are many times unknown by the people who have them.

“Most stroke [patients] will have at least one risk factor, whether or not they are aware of it,” said Dr. Jeffrey Ranaudo, a vascular surgeon in Manchester, Connecticut, affiliated with The Vascular Experts.

Dr. Humair Mirza, an interventional cardiologist at the Memorial Hermann Medical Group based in Texas, estimated that “fewer than 25 percent of stroke patients are aware of having prior risk factors.”

“The keyword here is ‘unknown’ because cardiovascular-related diseases — hypertension, high cholesterol, heart failure — are typically silent killers,” Nancy Mitchell, a registered nurse and writer at the resource website Assisted Living Center, told Healthline. “Many people don’t present early signs or symptoms, so they only learn of their condition after being hospitalized for a massive stroke. It happens often because risk factors for stroke develop slowly, most times over decades before manifesting.”

“It’s not that the risk factors are undetectable, but you have to do the necessary tests to pick them up. Most people avoid the doctor’s office and that’s a major issue in the battle against non-communicable diseases,” she added.

Dr. Aaron Loochtan, a vascular neurologist with OhioHealth, said that only a small subset of stroke patients do not have any risk factors and these tend to be younger patients (under age 50).

“This study helps to highlight the importance of recognizing stroke risk factors early,” Loochtan told Healthline. “Discovery and treatment of risk factors prior to causing disease is crucial. It is of the utmost importance that patients establish with a primary-care physician for annual well-being visits to make sure they are getting appropriate screenings to evaluate for cerebrovascular risk factors.”

Any low-density lipoprotein (LDL) cholesterol level at or above 130 mg/dL is a cause for concern, said Mitchell.

“The higher your ‘bad cholesterol’ levels, the more fatty deposits lurking in your bloodstream and forming blockages of plaque along your arteries. Those deposits create the clots that cut off the oxygen supply to the brain in an ischemic stroke,” she added.

Ranaudo said managing or changing modifiable risk factors is the best way for reducing stroke risk.

“These risk factors include cigarette smoking, poor dietary habits, sedentary lifestyle, and uncontrolled hypertension,” he told Healthline

“Treatment of high blood pressure, diabetes, obesity, high cholesterol, atrial fibrillation, and sleep apnea will help reduce one’s risk of stroke,” Loochtan added.

Ultrasound evaluation and medication to manage cholesterol and blood pressure are among the therapies available to prevent stroke, said Ranaudo.

“Identifying at-risk patients and performing simple clinical examinations and early referral to vascular specialists is the best way to get patients evaluated and treated quickly,” he said.