Stroke risk factors

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 High cholesterol levels are a risk factor for stroke. Cholesterol levels can be determined through the use of a safe and simple blood test often referred to as a lipid panel or profile. A comprehensive lipid panel can be used to evaluate different lipid types and levels. It may also include other specialized biomarkers for cardiovascular disease.

There are three main components of cholesterol which are; low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides. The LDL or "bad" cholesterol is the component associated with increased risk for developing blockages within arteries. Elevated levels of LDL increase the risk for developing heart disease, peripheral arterial disease, stroke and other health problems. The HDL or "good" cholesterol helps remove the LDL from the bloodstream. Higher levels of HDL help reduce the risk of cardiovascular disease. The term triglycerides refer to the fatty substance stored in fat cells within the body. Elevation of the blood triglyceride level can be caused by diabetes, hypothyroidism, and weight gain, excessive intake of alcohol, a fatty diet, kidney disease or liver disease. Special lab testing may be used to evaluate subtypes of HDL and LDL cholesterol.

The carotid arteries refer to the large pair of arteries located on each side of the front of the neck. They provide the primary blood supply to the brain. Fatty deposits and plaque can build up in the carotid arteries leading to critical narrowing, thus reducing the blood supply to the brain resulting in stroke. The progression of carotid artery disease is often silent (asymptomatic) If the plaque becomes ulcerated pieces can break loose, travel to the brain and/or to the back of the eye (retina) and block a blood vessel resulting in stroke. The buildup up plaque in an artery is referred to as atherosclerosis. The presence of significant atherosclerosis (blockages) in one or more carotid arteries is associated with increased risk for the presence of the same process in other areas of the circulatory system including the heart. 

Abnormal heart rhythms (arrhythmias) often occurs secondary to disorders of the heart's electrical system. An irregular heart rhythm causes the heart to pump less effectively. Normally, every heartbeat originates from a specialized group of cells with the upper right chamber of the heart (right atrium). This group of specialized cells is referred to as the sinoatrial or SA node, the sinus node or "pacemaker" of the heart. Signal spreads from the SA node throughout the atria (upper heart chambers) to the atrioventricular (A-V) node, another specialized group of cells near the middle of the heart. The A-V node connects to a group of specialized nerve fibers in the ventricles (lower heart chambers) which conduct the electric signal. The impulse travels down all of the specialized fibers to all parts of the ventricles causing the heart muscles to contract and facilitate blood flow. An exact route of bioelectrical signal propagation must be followed for the heart to pump properly and efficiently.

An irregular heart rhythm (arrhythmia) may occur for a number of reasons. Causes include chemical imbalances in the blood, coronary artery (large vessel) disease, microvascular disease (small vessel) in the heart muscle, autonomic (nerve) disorders, heart valve disorders, injury to the heart, and any condition which reduces blood flow to the heart. Prescription drugs may also have a positive or negative effect on the development of heart arrhythmia. Any condition which compromises the normal pacemaker (specialized group of cells) function in the heart will also lead to heart rate and rhythm abnormalities. 

 Atherosclerosis is a condition characterized by stiffening and narrowing of medium and large sized arteries. This process typically begins with blood vessel wall inflammation and the build-up of fatty substances or cholesterol on the interior portion of the artery wall. The build-up is often referred to as plaque. The development of plaque may partially or totally block blood flow through an artery. This process can cause a stroke in the brain, a heart attack or injury to another organ. The presence and degree of a blockage within an artery cannot be confirmed through the use of blood tests like cholesterol. Direct imaging of a blood vessel is required to confirm the presence of atherosclerosis (plaque). There are different methods which can be used to image blood vessels and/or blood flow through the vessel. One of the safest and most common methods is diagnostic ultrasound.  .

 Peripheral arterial disease (PAD) refers to diseases of blood vessels (arteries) outside the heart. This includes blood vessels of the neck, abdomen and extremities. It is a condition similar to coronary artery disease (CAD). In PAD fatty deposits build up along the interior of artery walls (plaque). The process can compromise blood flow to any tissue or organ in the body the blood vessels serve. This includes the brain, spine, kidneys, muscles, intestines, peripheral nerves, and bone. People with PAD have a higher risk of death from stroke and heart disease.  Peripheral arterial disease can be classified as large blood vessel disease (macroangiopathy) or small blood vessel disease (macroangiopathy). 

 The maintenance of blood viscosity (thickness) and clotting balance is a complicated process. Blood clotting or coagulation is a protective mechanism of the body to help seal up an injured blood vessel. In normal individuals, coagulation typically begins within 15-20 seconds after injury to a blood vessel. The availability and integrity of a specialized group of cells in the blood referred to as platelets along with a cascade of interdependent chemical events determines the pattern of clotting which occurs. There are many conditions which can adversely influence blood clotting mechanisms by either promoting the development of too much clotting or not enough. Both conditions increase the risk for tissue injury and stroke.  

The nicotine, carbon monoxide and other byproducts in cigarette smoke can damage the cardiovascular system; thus, increasing the risk for stroke. The use of birth control pills combined with cigarette smoking amplifies stroke risk.

Diabetes mellitus is an independent and modifiable risk factor for stroke. If you have Type 1 or 2 diabetes it is imperative that you control your blood sugar. Successful control requires regular monitoring and lifestyle changes. Diabetes mellitus contributes to the development of additional risk factors for stroke such as high blood pressure, high blood cholesterol, and abnormal patterns of blood fats (dyslipidemia) and being overweight. Diabetes is often associated with high levels of visceral (organ) fat, reduced muscle mass (lean mass) and increased body fat mass. Well managed diabetes reduces the risk for stroke, although individuals with the disease still have higher than normal risk. 

Diets high in saturated fat, trans fat and cholesterol can raise blood cholesterol levels. Diets high in sodium (salt) can increase blood pressure due to fluid retention. High caloric diets can lead to obesity including increased visceral fat levels. Research has revealed that a diet consisting of five or more servings of fruits and vegetables each day may reduce the risk of stroke. 

Physical inactivity has been associated with increased risk for developing heart disease, overweight/obesity, high blood pressure, high blood cholesterol and diabetes, all which increase your risk for stroke. It is important to exercise on a regular basis. It is also important to move throughout the day. Prolonged sitting and general inactivity increase the risk for high blood pressure and obesity. 

The phrase hemolytic anemia refers to disorders associated with abnormal shapes and fragility of red blood cells which carry oxygen. The two most common forms of hemolytic anemia are thalassemia (Mediterranean Anemia) and sickle cell anemia. Both conditions represent genetic disorders. Sickle cell anemia mainly affects African-American and Hispanic children. It is associated with abnormally shaped (sickled) red blood cells which are less able to carry oxygen to the body’s tissues and organs than normal red blood cells. In both conditions disfigured cells tend to be fragile and break apart (hemolysis) easy. They also tend to stick to blood vessel walls, a consequence which can result in reduced blood flow and tissue injury. When this process occurs in the brain it is referred to as a stroke. Work with your health care provider to prevent flare ups and manage them carefully.

Strokes tend to be more common within southeastern states, an area sometimes referred to as the “stroke belt” states.

The incidence of stroke is generally higher in populations with lower incomes. Contributing factors may include poor dietary habits, as well as higher smoking and obesity rates. Individuals with lower incomes may also have limited access to regular and quality healthcare.

Alcohol abuse can lead to medical complications, including stroke. If you drink alcohol, the American Heart Association/American stroke Association recommends no more than two drinks per day for men and no more than one drink per day for non-pregnant women. Pregnant women should not drink Alcohol abuse can lead to risk factors for stroke such as hypertension, diabetes in the development of blood clotting abnormalities. 

The most commonly abused drugs, including cocaine, amphetamines and heroin, have been associated with increased risk of stroke. The strokes associated with drug abuse occur more frequently in younger populations due to the higher incidence of illicit drug use and substance abuse.

Research has revealed that inadequate restorative sleep can lead to high blood pressure (arterial hypertension) and higher stress levels throughout today. Chronic sleep deprivation has also been associated with greater risk for obesity, edema, diabetes and hypertension, all risk factors for stroke. Sleep disorders such as sleep apnea which reduce oxygen levels during the sleep cycle may contribute to chronic vascular inflammation and increased risk for stroke during the hypoxic (low oxygen) periods while sleeping. The presence of acute or chronic lung disease may amplify stroke risk associated with sleep disorders.