Stroke Risk Factors

• The first goal in stroke prevention is to identify persons at high risk for stroke including those with nonmodifiable risk factors for whom more intense treatment of modifiable risk factors may be indicated.¹

• Stroke risk factors can be broadly categorized as nonmodifiable, modifiable and potentially modifiable. Nonmodifiable risk factors include age, ethnicity, and family history.

Nonmodifiable risk factors

• After the age of 55, a person’s chance of having a stroke more than doubles for each decade of life.² The risk of stroke increases if there is a family history of stroke, especially if a first-degree relative has had a stroke.²

• Stroke is generally more common in men than in women but more women who have stroke die than men, because they are significantly older than men when they experience a stroke and in poorer health.²

• Ethnicity is a stroke risk factor: Blacks and Asians have a much higher risk of death from a stroke than do whites .²

• Having experienced one or more transient ischemic attack (TIA) makes a person 10 times more likely to have a stroke than someone of the same age and sex who has not.²

 Modifiable risk factor

• Modifiable risk factors for stroke include smoking (2-fold risk), high blood pressure, diabetes, elevated cholesterol, low HDL (high-density lipoprotein) cholesterol (2-fold), atrial fibrillation (4-fold) asymptomatic carotid stenosis (2-fold risk), physical inactivity (3-fold), obesity, binge drinking, sickle cell disease, and estrogen therapy.¹

• High blood pressure causes about 50% of ischemic strokes and also increases the risk of hemorrhagic stroke.² High blood pressure doubles the risk of stroke.³

• Strokes happen twice as often in people with diabetes and hypertension compared to people with hypertension alone.⁴

• Tobacco use doubles the risk of ischemic stroke and quadruples the risk of hemorrhagic stroke.⁴

• The use of oral contraceptives combined with tobacco use greatly increases stroke risk.⁴

• People with diabetes can have up to six times greater a risk of stroke than people without diabetes.⁴

• Overweight and obesity are independent risk factors for ischemic stroke in Japanese men (3-fold risk).⁵

• Sickle cell disease and thrombophilias are important risk factors for stroke in young people. ⁶

• Unhealthy diets that are high in saturated fat, trans fat and salt increase the risk of stroke.⁴

• A review in the journal Stroke of 26 stroke studies suggests that people who consumed 40 to 60 grams of alcohol ─ about three to four drinks ─ had an almost threefold increase in the risk of stroke within the next 24 hours. ⁷ A similar increase was linked to having more than 150 grams of alcohol, or about 10 standard drinks, in the past week.⁷

Potentially modifiable risk factors

• Potentially modifiable risk factors include migraine with an aura, the metabolic syndrome, >4 drinks of alcohol per day, drug abuse, hyperhomocysteinemia, and increased lipoprotein(a).¹

• Researchers also found that those who had a cold, flu or other infections were two to three times more likely than others to suffer a stroke over the next seven to 30 days.⁷

• In the INTERSTROKE study, the average age of study subjects was age 61 years, 37% of the sample were women, and 78% were diagnosed with an ischemic stroke.⁸ The results of this study suggest that nine modifiable risk factors are associated with the risk of stroke worldwide. Using self-reported hypertension, current smoking status, an elevated waist to hip ratio, unhealthy dietary and exercise practices, upwards of 83% of all cases of stroke were accounted for by these risk factors.⁸

Sources

1. Goldstein L B., Bushnell CD, Adams RJ, et al. Guidelines for the primary prevention of stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. Feb 2011;42(2):517-584.

2. American Heart Association Heart and Stroke Statistical Update2010.

3. Baba Y, Ishikawa S, Kayaba K, Gotoh T, Kajii E. High pulse pressure is associated with increased risk of stroke in Japanese: The JMS Cohort Study. Blood Press. Sep 13 2010.

4.Goldstein LB, Adams R, Alberts MJ, et al. Primary prevention of ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council: cosponsored by the Atherosclerotic Peripheral Vascular Disease Interdisciplinary Working Group; Cardiovascular Nursing Council; Clinical Cardiology Council; Nutrition, Physical Activity, and Metabolism Council; and the Quality of Care and Outcomes Research Interdisciplinary Working Group: the American Academy of Neurology affirms the value of this guideline. Stroke. Jun 2006;37(6):1583-1633.

5. Yonemoto K, Doi Y, Hata J, et al. Body mass index and stroke incidence in a Japanese community: the Hisayama study. Hypertens Res. Nov 25 2010.

6. Kenet G, Lutkhoff LK, Albisetti M, et al. Impact of thrombophilia on risk of arterial ischemic stroke or cerebral sinovenous thrombosis in neonates and children: a systematic review and meta-analysis of observational studies. Circulation. Apr 27 2010;121(16):1838-1847.

7. Guiraud V, Amor MB, Mas JL, Touze E. Triggers of ischemic stroke: a systematic review. Stroke. Nov 2010;41(11):2669-2677.

8. O’Donnell M. J., Xavier D, Liu L, et al. Risk factors for ischaemic and intracerebral haemorrhagic stroke in 22 countries (the INTERSTROKE study): a case-control study. Lancet. Jul 10 2010;376(9735):112-123.