A stroke occurs when the blood supply to part of the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. It can be caused by a blockage in an artery leading to the brain (ischemic stroke) or the leaking or bursting of a blood vessel in the brain (hemorrhagic stroke). Knowing who is at high risk for stroke is important for prevention. Certain factors can increase a person’s chances of having a stroke.
Age
The risk of stroke increases with age. People over the age of 55 are more likely to have a stroke than younger people. According to the Centers for Disease Control and Prevention (CDC), over 75% of strokes occur in people over the age of 65. After age 55, the risk of stroke doubles every 10 years. As the large “baby boomer” generation ages in the United States, stroke prevalence is expected to rise substantially.
Gender
Stroke is more common in men than in women across all age groups. However, more than half of stroke deaths occur in women. The risk factors and the types of stroke experienced can differ between men and women. Pregnancy, hormone therapy, and birth control pills can increase stroke risk in some women. Women are also more likely to have strokes at older ages as their risk increases dramatically after menopause.
Family history
Having a family history of stroke increases your own risk. If you have a parent, grandparent, or sibling who has had a stroke, you are at a greater genetic risk. African Americans have a higher incidence of stroke than Caucasians and are more likely to have a family history of stroke and stroke risk factors.
Race
African Americans have almost twice the risk of first-ever stroke compared to Caucasians. They also have a higher rate of death from stroke. Reasons for these racial disparities are not fully understood but may be due to higher rates of hypertension, diabetes, and obesity. Hispanics also have an increased risk compared to non-Hispanic whites.
High blood pressure
Hypertension, or high blood pressure, is the single most important risk factor for stroke. Chronic elevated blood pressure damages arteries over time, making them more narrow, hardened, and prone to blockage. According to the American Heart Association, 77% of people who have their first stroke have blood pressure higher than 140/90 mm Hg. Regularly monitoring and controlling blood pressure is key to reducing stroke risk.
Smoking
Smoking cigarettes promotes atherosclerosis – the buildup of fatty deposits on artery walls. It increases clotting factors in the blood and damages artery linings. In addition to cardiovascular diseases, smoking approximately doubles the risk of ischemic stroke. The more you smoke, the higher your risk. Compared to never smokers, smoking less than 1 pack a day triples stroke risk and smoking more than 2 packs a day increases risk 8-10 times.
Diabetes
Diabetes is a major risk factor for stroke, increasing risk 1.5 to 3 times higher compared to non-diabetics. High blood glucose levels over time damage nerves and blood vessels. About a third of people who have diabetes die of stroke. Controlling blood sugar levels with medication, diet and exercise is important to lower stroke risk.
Physical inactivity
Lack of exercise is associated with increased risk of stroke and other cardiovascular diseases. Being inactive promotes atherosclerosis and hypertension. Regular aerobic activity for at least 30 minutes per day on most days can help lower stroke risk. Even moderate amounts can be beneficial.
Obesity
Having a body mass index (BMI) over 30 is a significant risk factor for ischemic stroke. Body fat, especially around the waist, produces substances that promote atherosclerosis. Losing even 10 pounds can markedly reduce blood pressure. A healthy diet and regular exercise are key to maintaining an optimal weight.
High cholesterol
Cholesterol promotes the buildup of plaque in arteries (atherosclerosis) which can lead to blockage and stroke. Total cholesterol levels above 240 mg/dL are considered high risk. LDL (“bad” cholesterol) levels above 100 mg/dL also raise concerns. Medications like statins can help lower cholesterol and stroke risk for those at high risk.
Atrial fibrillation
This abnormal heart rhythm allows blood to pool in the heart chambers and form clots, which can then travel to the brain causing stroke. People with atrial fibrillation are around 5 times more likely to have a stroke than the general population. Blood thinners are commonly prescribed to reduce clot risk.
Other heart disease
Conditions like coronary artery disease, heart failure, and heart defects increase the chance that clots will form and cause blockages in blood vessels in the brain. Stroke risk is higher within days or weeks after a heart attack. Angina, heart valve problems, and arrhythmias can also raise stroke risk.
Prior stroke/TIA
Someone who has had a stroke is at high risk of having another one. About 25% of people who recover from their first stroke will have another stroke within 5 years. Transient ischemic attacks (TIAs), or “mini-strokes”, also raise the risk of an actual stroke occurring. Preventative treatment is extremely important for stroke survivors.
Sickle cell disease
This inherited blood disorder affects hemoglobin and makes blood cells rigid and fragile. These misshapen cells can clog blood vessels, limiting blood flow to the brain. Children and young adults with sickle cell have a high risk of stroke. Blood transfusions help lower this risk.
Heavy alcohol consumption
Drinking too much alcohol regularly can raise blood pressure, cause heart disease and lead to stroke. Consuming more than 2 drinks per day for men and 1 drink per day for women raises stroke risk substantially. Alcohol can also interact negatively with other medications.
Illegal drug use
Cocaine, amphetamines, and other illicit drugs have been linked to increased stroke risk, especially in young adults. Drug abuse can lead to major health problems like high blood pressure, heart disease, and stroke. Injection drug use also raises risk due to infection.
Oral contraceptives
Use of birth control pills, especially if combined with other stroke risk factors like smoking, can increase the chance of blood clots. Estrogen-containing contraceptives appear to pose the highest risk. However, the overall chance of stroke for most women taking oral contraceptives is still low.
Hormone therapy
Postmenopausal women who take hormone replacement therapy (HRT) containing estrogen plus progestin may have an increased risk of stroke and blood clots. But this risk seems mainly limited to oral, not transdermal, HRT. There are safer alternatives for menopausal symptoms.
Sleep apnea
Obstructive sleep apnea, where breathing stops and starts during sleep, has been linked to higher stroke risk. It appears to damage blood vessels and promote high blood pressure, arrhythmias, and glucose intolerance – all stroke risk factors. Treatment with CPAP (continuous positive airway pressure) may help lower stroke risk.
| Risk Factor | How it Increases Stroke Risk |
|---|---|
| Old age (over 55) | The aging process damages blood vessels. |
| Male gender | Hormones and lifestyle factors play a role. |
| Family history | Genetics contributes to stroke risk. |
| African American race | Higher rates of related conditions like hypertension. |
| High blood pressure | Chronically damages blood vessel walls. |
| Smoking | Promotes atherosclerosis and blood clots. |
| Diabetes | Damages nerves and blood vessels. |
| Obesity | Can lead to high blood pressure and atherosclerosis. |
| High cholesterol | Leads to clogged arteries. |
| Atrial fibrillation | Allows blood clots to form in the heart. |
| Heart disease | Increases chance of blood clots traveling to the brain. |
| Prior stroke | Indicates existing blood vessel damage. |
Prevention
Despite the many risk factors, up to 80 percent of strokes are preventable through lifestyle changes and medical management of conditions like hypertension and atrial fibrillation. Steps to reduce your risk include:
– Maintaining healthy blood pressure, cholesterol and blood sugar levels
– Not smoking
– Eating a diet high in fruits, vegetables, and whole grains
– Exercising regularly
– Limiting alcohol intake
– Maintaining a healthy weight
– Treating conditions like high blood pressure, diabetes, and sleep apnea
– Taking preventive medications like blood thinners if at high risk
Knowing the risk factors, getting regular checkups, and leading a healthy lifestyle are key to lowering your chances of having a stroke. Prompt treatment at the first signs of stroke is also critical to avoid permanent disability and life-threatening complications. Being aware and taking preventive action offers the best protection against stroke.
Conclusion
Stroke can occur at any age but becomes more common over 55. Major risk factors like hypertension, smoking, obesity and heart disease can often be modified through lifestyle changes and medical treatment. While some factors like age, gender and race cannot be changed, being aware of your personal risk helps you and your doctor take steps to lower your chances of having a stroke. Controlling modifiable risk factors through prevention and prompt treatment of warning signs are the best ways to avoid the potentially devastating consequences of stroke.