Stroke Risk Factors: What's the 411?
Embedded Files
Cerebrovascular diseases, including stroke, were the #5 cause of death in the United States in 2020 [1].
Cerebrovascular diseases, including stroke, were the #5 cause of death in the United States in 2020 [1].
Chances are, you know someone who has suffered a stroke. Cerebrovascular accidents, a.k.a strokes, are among the most devastating of these conditions. There are many risk factors for stroke; we can break up the primary factors into either "modifiable" or "non-modifiable" risk factors. While we cannot change the "non-modifiable" risk factors, we can reduce our overall risk for stroke via management of our modifiable risk factors!
First of all, what is a stroke?
A stroke is an issue of bloodflow to the brain. The brain requires blood delivered by a complex network of vessels, also known as arteries (see Figure 1) in order to receive nutrients to function, including oxygen. When deprived of oxygen, the brain cannot deliver commands to the body to do everything it needs to do to function, including breathe and walk! The bloodflow issue can be temporary, as in the case of a transient ischemic attack (or TIA), where the artery is blocked by debris that manages to pass through. Many times, however, a stroke has far more lasting impacts.
There are several major blood vessels that deliver blood to the brain, including the carotid and vertebral arteries, that branch into a series of arteries that serve the brain called the Circle of Willis. A stroke is either a blockage or bleed of these arteries, reducing the ability of that blood vessel to deliver blood to the brain. A stroke can occur at any of these arteries; the portion of the brain that receives blood from the affected artery determines what symptoms an individual will have. These symptoms range from weakness, dizziness, difficulties with vision, speech, and many more.
Figure 1: Cerebral angiogram, imaging of blood vessels in the brain.
Lipothymia, Public domain, via Wikimedia Commons
Non-modifiable risk factors
Some of us are at an increased risk for stroke due to qualities that we can't change. These include:
Age[2]
Family history
Ethnicity[2]
Sex[2]
Prior history of stroke
Genetic disorders[2]
Migraines, for younger people [3]
Age
In general, the older someone is, the higher their risk for stroke: each decade after 55 years of age, our risk doubles [2]. Despite this alarming statistic, we can mitigate our risk as we get older with early screening and management of modifiable risk factors (see below!). Approximately 10-15% of all strokes occur in younger populations[4], but these strokes are more heavily influenced by external factors such as hormone use, such as hormonal contraceptives. A higher percentage of strokes in younger individuals have no clear cause of the stroke [4]. Emerging research suggests that for those under 35 years of age, presence of migraines increases stroke risk [3]. Screening for stroke risk begins early!
Ethnicity
While those hailing from different countries have varied risks for stroke, one of the most stark examples of ethnicity impacting stroke risk is in the United States. In comparison to age-matched white people, black people have at least twice the risk for stroke, especially at middle age [2,4]. Socioeconomic status may be a significant factor, fundamentally impacting access of care, education and awareness of stroke symptoms, and ability to manage high blood pressure. Further, the role of systemic racism in medicine on stroke prevalence and recovery is unclear but undoubtedly significant.
Sex
Both cisgender women and transgender women may be at a higher risk for stroke due to hormonal contraceptive use and use of gender-affirming hormonal therapies to transition, including estrogen. One in five women will have a stroke!
Prior history of stroke
Despite the importance of exercise, an individual post-stroke is less likely to get adequate exercise and more likely to spend time sedentary [5], which can further increase risk for another stroke. It is safe to exercise after you've had a stroke with very few exceptions; research tells us that high intensity training, where the heart rate increases and breathing becomes more labored, has been shown to improve one's ability to perform daily tasks and walk after stroke -- even while still in the hospital [6,7].
Modifiable risk factors
The good news is, there are many factors we can control when it comes to preventing stroke. Modifiable risk factors are especially important to consider if you have a strong family history, or if you yourself have had a history of stroke or transient ischemic attacks. Some of these modifiable risk factors are conditions that, while may not be curable, can be very well controlled with medication and/or lifestyle changes, such as atrial fibrillation [2]. Others include:
High blood pressure
High cholesterol
Diabetes
Atrial fibrillation
Smoking
Drug and alcohol use
Blood pressure
The most important risk factor above is management of blood pressure. Blood pressure is a measure of pressure in your arteries, most often measured at the doctor's office with the blood pressure cuff placed on the upper arm. Critical values of high blood pressure, including 200/100 mm Hg or more, are considered medical emergencies because the vessels in the brain are at risk for bursting and bleeding under such high pressures. Imagine blowing up a balloon: if you blow in too much air, the skin of the balloon is unable to sustain the pressure, and pops. Additionally, some of the effects of high blood pressure are cumulative over a lifespan; prolonged high blood pressure can cause disease of the small arteries that feed deep areas of the brain, including the brainstem, where some 25% of all ischemic strokes occur [2].
Figure 2. Dr. Jess taking a patient's blood pressure.
Blood pressure continued:
Blood pressure can be influenced by genetics and family history, but other strong modifiable factors include poor dietary intake, stress, physical inactivity, and excessive alcohol consumption [8]. While regular visits to the doctor can help with strategies for these factors, it's easier than ever now to measure blood pressure at home with relatively inexpensive equipment. Lifestyle changes including exercise, as well as medication, can go a long way in managing blood pressure. Despite this, high blood pressure disproportionally affects black people as compared to their age-matched white counterparts. Community-based educational interventions have attempted to increase awareness of stroke symptoms and the importance of blood pressure screenings [8,9], but this underscores the need for all health care providers, from doctors to physical therapists, ensure they are providing adequate education and resources for patients to screen blood pressure, and advocate for such resources in community settings.
Figure 3. Screencaption of the American Stroke Association's Stroke Risk Assessment.
Assess YOUR risk!
There are free, online tools you can use to determine your risk for stroke.
American Stroke Association Stroke Risk Assessment - if you select an answer that is "higher risk" more often than "lower risk", you should get screened by your doctor to determine how you can reduce your risk.
Carle Health Stroke Risk Estimator - this quiz asks the same questions as the above, but in an online module that is easy to use and clearly categorizes your risk. While the page is titled, "Test Your Stroke Knowledge", the quiz actually assesses your overall risk.
Take Action!
Even if your stroke risk is high, or you've had a stroke in the past, it is never too late to begin working to reverse your risk. One of the best ways is through exercise! Exercising at moderate intensity is safe for almost everyone, but if you have concerns, bring them up with your doctor.
But how much exercise do you need? The American College of Sports Medicine recommends 150 minutes per week of moderate intensity exercise, and/or 75 minutes per week of high intensity exercise, spread out throughout the week [10]. At moderate intensity, you should be able to sing a line in a song, or say a phrase while exercising, but require a deep recovery breath between phrases. At high intensity, you may only be able to say a few words before needing a recovery breath. There is nothing wrong with exercising at a low intensity, but try to sprinkle in bouts of moderate to high intensity in intervals -- during your walk or wheel, go up a hill, or increase your pace for 30 seconds at a time. Interval training such as this is also effective! If you feel short of breath at rest or earlier than expected when exercising, or have chest pain a.k.a angina that increases with exercise, please consult with your doctor before starting an exercise regimen. You may need to take extra precautions to ensure you're safe!
References
Curtin SC, Tejada-Vera B, Bastian BA. Deaths: Leading Causes for 2020. Natl Vital Stat Rep. 2023;72(13):1-115.
Murphy SJ, Werring DJ. Stroke: causes and clinical features. Medicine (Abingdon). 2020;48(9):561-566. doi:10.1016/j.mpmed.2020.06.002
American Heart Association. American Heart Association | To be a relentless force for a world of longer, healthier lives. www.heart.org. Published 2018. https://www.heart.org/en
Potter TBH, Tannous J, Vahidy FS. A Contemporary Review of Epidemiology, Risk Factors, Etiology, and Outcomes of Premature Stroke. Curr Atheroscler Rep. 2022;24(12):939-948. doi:10.1007/s11883-022-01067-x
Fini NA, Holland AE, Keating J, Simek J, Bernhardt J. How Physically Active Are People Following Stroke? Systematic Review and Quantitative Synthesis. Phys Ther. 2017;97(7):707-717. doi:10.1093/ptj/pzx038
Hornby TG, Reisman DS, Ward IG, et al. Clinical Practice Guideline to Improve Locomotor Function Following Chronic Stroke, Incomplete Spinal Cord Injury, and Brain Injury. J Neurol Phys Ther. 2020;44(1):49-100. doi:10.1097/NPT.0000000000000303
Moore JL, Nordvik JE, Erichsen A, et al. Implementation of High-Intensity Stepping Training During Inpatient Stroke Rehabilitation Improves Functional Outcomes. Stroke. 2020;51(2):563-570. doi:10.1161/STROKEAHA.119.027450
Schmidt BM, Durao S, Toews I, et al. Screening strategies for hypertension. Cochrane Database Syst Rev. 2020;5(5):CD013212. Published 2020 May 7. doi:10.1002/14651858.CD013212.pub2
Gardois P, Booth A, Goyder E, Ryan T. Health promotion interventions for increasing stroke awareness in ethnic minorities: a systematic review of the literature. BMC Public Health. 2014;14:409. Published 2014 Apr 28. doi:10.1186/1471-2458-14-409
Physical activity guidelines. ACSM_CMS. https://www.acsm.org/education-resources/trending-topics-resources/physical-activity-guidelines
Page updated
Report abuse