Definition and Overview
Stroke risk factors are biological, environmental, and behavioral factors that statistically and significantly increase the likelihood of stroke occurrence. Risk factors are classified into non-modifiable and modifiable categories, with active management of the latter being central to primary stroke prevention.
The INTERSTROKE study (O'Donnell et al., 2010) analyzed more than 6,000 stroke patients across 22 countries and confirmed that 10 modifiable risk factors (hypertension, smoking, abdominal obesity, diet, physical inactivity, diabetes mellitus, excessive alcohol consumption, cardiac causes, apolipoprotein ratio, and psychosocial stress) account for approximately 90% of the population-attributable risk for all strokes [1].
Non-Modifiable Risk Factors
Age is the most potent risk factor; the risk of stroke approximately doubles with each decade after age 55 and rises sharply after age 75.
Regarding sex, males have a somewhat higher overall risk; however, females exhibit unique risk profiles related to pregnancy, oral contraceptive use, migraine, and atrial fibrillation-associated stroke.
For genetic and family history factors, having a first-degree relative with early-onset stroke (before age 55 in males, before age 65 in females) increases risk. Monogenic conditions such as hereditary thrombophilia and CADASIL also exist.
Regarding race/ethnicity, certain populations including Black and Hispanic individuals demonstrate higher stroke incidence and mortality rates.
Modifiable Risk Factors
Hypertension, with a population-attributable risk of 35 to 50%, is the single greatest risk factor for stroke [2]. Meta-analysis results have shown that blood pressure reduction decreases stroke risk by approximately 38% [4].
Atrial fibrillation is a powerful risk factor that increases stroke risk approximately 5-fold [3]. Anticoagulant therapy (DOACs or warfarin) reduces the risk of cardioembolic ischemic stroke by approximately 60 to 70%.
Smoking increases the risk of ischemic stroke approximately 1.5 to 2-fold, and cessation reduces risk to near-normal levels within several years.
Diabetes mellitus increases stroke risk approximately 2-fold through promotion of small vessel disease and atherosclerosis, and glycemic control contributes to stroke prevention.
In dyslipidemia, elevated LDL cholesterol promotes atherosclerosis, and statin therapy significantly reduces stroke risk.
Obesity and physical inactivity are also independent risk factors. A body mass index (BMI) of 30 or above, abdominal obesity, and physical inactivity increase stroke risk through metabolic syndrome and multiple risk factor pathways.
Additional risk factors include obstructive sleep apnea, chronic kidney disease, psychosocial stress, excessive alcohol consumption, dietary factors (excessive sodium, saturated fat), and substance abuse including cocaine.
Risk Assessment
Stroke risk can be evaluated using composite risk factor scoring tools. The Framingham Stroke Risk Score, SCORE, and CHA₂DS₂-VASc (specific to atrial fibrillation patients) are utilized in clinical practice.
Carotid ultrasonography with intima-media thickness (IMT) measurement can serve as an early marker of subclinical atherosclerosis.
Prevention Strategies
The cornerstone of primary prevention (in patients who have not experienced stroke) is active management of modifiable risk factors.
Blood pressure management with a target of less than 130/80 mmHg is generally recommended. Lifestyle modifications (low-sodium diet, exercise, weight reduction) are combined with pharmacological therapy.
Strategies include early detection of atrial fibrillation with anticoagulant therapy, diabetes control (HbA1c target below 7%), statin therapy for dyslipidemia, smoking cessation, at least 150 minutes of moderate-intensity exercise per week, and a Mediterranean-style diet.
In patients with multiple risk factors, an integrated management approach is more effective than addressing individual risk factors in isolation [1].
Prognosis
Stroke is a largely preventable disease through risk factor management. Epidemiological data confirm that population-level improvements in blood pressure, smoking, and diabetes management have contributed to declining stroke incidence rates [2]. However, due to population aging and the growing prevalence of diabetes and obesity, the absolute number of stroke patients continues to rise, underscoring the increasing importance of proactive risk factor management.