Introduction
A stroke is a life-threatening disease which, despite the best possible therapy, can still lead to serious consequential damage or even death in many cases. Therefore it is useful to better understand the causes and risk factors of the disease in order to reduce the probability of a stroke by early prevention.
The different causes of a stroke
There are risk factors that we cannot influence. Among these not changeable risk factors rank: In addition there are risk factors, which we can influence and/or treat. Among these changeable risk factors count:
- Age
- Genetic predisposition
- Male sex
- High blood pressure (arterial hypertension)
- Diabetes mellitus
- High cholesterol levels
- Overweight (Adipostias)
- Smoking
- Stress
- Alcohol consumption
- Lack of exercise
- Heart disease, like atrial fibrillation or an open Foramen ovale
- Coagulation disorders
- Migraine with aura
- Taking medication, such as oral contraceptives or cortisone
High blood pressure, also called arterial hypertension, is the most important risk factor for the development of strokes.
This is partly due to the direct increase in the risk to 4-5 times its normal level, but also to its influence on other risk factors, such as arteriosclerosis, which are promoted by high blood pressure. In addition, high blood pressure is by far the most common risk factor, accounting for 25-40% of the population. High blood pressure promotes the development of vascular calcifications, the development of brain aneurysms and can itself lead to cerebral hemorrhages.
Furthermore, high blood pressure is the most controllable risk factor for strokes. In most cases, it can be adequately treated with a healthy diet, sufficient physical exercise and medication, which is associated with a significant reduction in the risk of stroke. Along with high blood pressure, atrial fibrillation is one of the most important risk factors for the development of a stroke.
It is a cardiac arrhythmia associated with ineffective, uncoordinated contractions of the atrial muscles. These create turbulent flows in the atria, which increases the risk of blood clots forming. If such a blood clot, also known as a thrombus, is formed in the left atrium, it can enter the brain vessels through the carotid artery and lead to occlusion of these vessels.
This process is known as thromboembolism and is one of the most common causes of strokes. To prevent the formation of such thrombi, adequate anticoagulation with Marcumar or newer drugs (so-called NOAKs) should always be administered after the diagnosis of atrial fibrillation. The following topic may be of interest to you: Anticoagulant studies have shown a clear link between cigarette consumption and the risk of stroke.
For example, smokers have a 2-4 times higher risk of suffering a stroke than non-smokers. This increase in risk from smoking is mediated by the promotion of high blood pressure and arteriosclerosis, among other things. Therefore, the consumption of cigarettes is not recommended in any case in order to keep the risk of a stroke low.
Even if the risk from stopping nicotine consumption does not fall back to the baseline value, a significant risk reduction from stopping nicotine consumption can be observed. Diabetes mellitus represents a decisive risk factor for the development of strokes. Approximately one in five stroke patients is diagnosed with diabetes mellitus.
This correlation is mainly due to the significantly higher risk of arteriosclerosis, which ultimately causes the stroke. Excessively high blood sugar levels lead to increased plaque formation in the blood vessels, resulting in increasing vascular damage and constriction. Especially in combination with other risk factors, diabetes can lead to an enormous increase in risk.
While diabetes itself leads to a 2-4-fold increase in risk, this value rises to 10-12 times in combination with simultaneous high blood pressure. Since elevated cholesterol promotes the development of arteriosclerosis, this can also lead to an increased risk of stroke. This is especially true for cholesterol levels of more than 240 mg/dl.
However, high cholesterol levels are less significant in the development of strokes than in that of heart attacks. Obesity is an important risk factor for strokes, especially due to the connection with arteriosclerosis, diabetes and high blood pressure. It is assumed that obesity, i.e. a BMI of >30kg/m2, causes a 2-3-fold increase in the risk of stroke.However, since abdominal fat is the main cause of this risk increase, the abdominal girth is usually also used for risk assessment in addition to the BMI.
Thus, women with an abdominal girth of >88cm have a significantly increased risk, while this limit is 102cm for men. In the meantime, it has become common knowledge that exercise is good for health. Lack of physical activity, on the other hand, can increase the risk of various diseases such as dementia, cardiovascular diseases and strokes.
This connection is mainly due to the fact that lack of exercise is often associated with high blood pressure, arteriosclerosis and diabetes. In order to keep the risk of a stroke as low as possible, regular physical activity is therefore recommended, even if it means simply taking a long walk. The role of alcohol as a risk factor for strokes depends largely on the amount consumed.
Studies have shown that moderate alcohol consumption only slightly increases the risk of cerebral hemorrhages. However, if alcohol is consumed in large quantities, the risk of cerebral hemorrhage and vascular occlusion in the brain increases. For women the limit is 0.3l beer or 0.15l wine and for men 0.5l beer or 0.25l wine daily.
The connection between stress and an increased risk of stroke has been proven in several studies. These studies conclude that stress at work in particular is a decisive factor in this connection. Affected are mainly employees who carry out a stressful job that is associated with little independent control.
The risk increase is estimated at 20-30% and mainly includes the increased incidence of strokes due to vascular occlusion, whereas cerebral haemorrhages are equally frequent as a cause. Recent studies have shown an association between the presence of migraine and the risk of stroke. However, this is only observed in migraine headaches that are accompanied by a so-called aura.
The term aura is used to describe symptoms such as impaired vision or sensation, but also stomach problems or nausea that occur before the onset of migraine. The risk increase is approximately a factor of 2, but it should be noted that most migraine patients are very young and generally have a very low risk of stroke. Thus, even a risk increase of factor 2 has only a small influence on the absolute risk.
Nevertheless, migraine patients with an aura should consciously take care to avoid possible avoidable risk factors, such as obesity, in order to prevent the development of strokes. Diseases of the heart valves can also increase the risk of blood clots forming and thus the risk of strokes. The aortic valve is particularly affected by this, since after this the blood is pumped directly into the brain vessels.
If calcification of the valve occurs and thus a narrowing occurs, this is called aortic valve stenosis. From a certain degree of narrowing, the indication for a valve replacement is given. These artificial valves are usually made of plastic, which means that the risk of thrombus formation is high with this material.
For this reason, anticoagulation is also performed after the insertion of such valves to prevent the development of a stroke. Congenital and acquired disorders of blood clotting can increase the risk of stroke. These have in common that they increase the coagulability of the blood and thus promote the formation of blood clots.
This is the case, for example, with a protein C and protein S deficiency. In these cases, proteins are missing which normally lead to effective inhibition of blood clotting. Triggered by various factors, a deficiency of these proteins can occur, which then results in increased blood clotting. Other diseases of this spectrum include Factor V Leiden or resistance to activated protein C.
