The risk of stroke from common risk factors, such as high blood pressure, smoking, and diabetes, increases with age. As people grow older, their blood vessels become less flexible and more prone to blockages, making them more susceptible to stroke. In addition, the risk of stroke is influenced by other factors, such as lifestyle choices and family history, which may become more pronounced as people age.
Although diabetes and high blood pressure have long been recognized as stroke risk factors, a recent study suggests that the risk may actually diminish with age. The research was released online in the latest issue of Neurology®, the medical journal of the American Academy of Neurology.
A person’s risk can be reduced by taking medication to treat high blood pressure and diabetes, according to study author George Howard, DrPH, of the University of Alabama at Birmingham School of Public Health. “Our findings suggest that while other risk factors do not change with age, their association with stroke risk may be significantly diminished as people get older. These variations in risk factors suggest that age may affect whether a person is considered to be at high risk for stroke.”
28,235 people who had never had a stroke participated in the study. 59% of this group were white, and 41% were Black. Follow-up with the participants lasted an average of 11 years.
Our findings suggest that while other risk factors do not change with age, their association with stroke risk may be significantly diminished as people get older. These variations in risk factors suggest that age may affect whether a person is considered to be at high risk for stroke.George Howard
At the start of the study, participants were interviewed and given physical exams to assess risk factors. Risk factors included high blood pressure, diabetes, smoking, atrial fibrillation, heart disease and left ventricular hypertrophy which is the thickening of the heart’s left ventricle. Because of the well-known higher stroke risk in Black people, race was also considered as part of the assessed risk factors, Howard added.
Every six months, researchers checked in with participants and confirmed strokes by examining medical records. Over 276,074 person-years, there were 1,405 strokes during the study. Person-years are a measure of both the number of participants in the study and the duration of each participant’s participation.
Three age groups of participants were created, and they were compared. Depending on how the researchers were analyzing the data, the age ranges for those groups varied a little. Participants in the younger group typically ranged in age from 45 to 69, while those in the middle group were in their late 60s to early 70s, and those in the older group were 74 and older.
Researchers discovered that people with diabetes in their younger years were approximately twice as likely to have a stroke as people of similar age who did not have diabetes, whereas people with diabetes in their older years were approximately 30% more likely to have a stroke than people of similar older age who did not have diabetes.
Researchers also discovered that people with high blood pressure in their younger age group had an 80% greater risk of having a stroke than people of similar age without high blood pressure, whereas people with high blood pressure in their older age group had a 50% lower risk compared to people of similar age without high blood pressure.
Furthermore, when researchers looked at race as a risk factor, they discovered that Black participants in the younger age group had a higher stroke risk than white participants in that group. The race disparity shrank as people got older. Researchers found no age-related change in risk for stroke risk factors such as smoking, atrial fibrillation, and left ventricular hypertrophy.
“It’s important to note that our findings do not imply that treating high blood pressure and diabetes becomes less important as you get older,” Howard said. “Such treatments are still critical to a person’s health. However, as people age, it may be prudent for doctors to focus on risk factors such as atrial fibrillation, smoking, and left ventricular hypertrophy.”
Howard also noted that even if the impact of risk factors decreases with age, the total number of people with strokes at older ages may still be higher because overall stroke risk increases with age. For example, researchers estimate that about 2.0% of people with normal blood pressure had a stroke, compared to 3.6% of people with high blood pressure in the younger age group. In the older age group, 6.2% of people with normal blood pressure and 9.3% of people with high blood pressure had a stroke.
One limitation of the study was that participants’ risk factors were only assessed once at the beginning of the study, and it’s possible that they changed over time.