Strokes
Stroke Causes and Risk Factors
A stroke is a medical emergency that requires
attention due to its debilitating effects. It can affect people of all
ages, but the risk increases with age. The risk of stroke can be increased
by certain medical conditions, life style factors and heredity.
The risk factors can be divided into two
categories:
I. Controllable factors.
II. Uncontrollable factors.
I. Controllable factors include those factors that can be controlled
with medication or diet (medical conditions), or simply changing the lifestyle
habits and choices. The controllable factors are divided into two categories:
1. Medical conditions
that can be treated:
Hypertension (High Blood Pressure). High blood pressure
is one of the major risk factors for both ischemic and hemorrhagic
stroke. The risk of stroke increases 4 to 6 times when the person
has high blood pressure.
The blood pressure measures the force of blood pushing against
the walls of the arteries. When the blood pressure is high, the
heart has to pump harder to move the blood through the body, which
leads to weak blood vessels and damage to major organs in the
body. Normal blood pressure is 120/80 or below, while a blood
pressure reading of 140/90 and above is considered high blood
pressure (or hypertension). |
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Atrial Fibrillation (AF) is a medical condition where the heart
beats irregularly because the two upper chambers of the heart beat rapidly
and unpredictably. Atrial fibrillation increases the risk of stroke
up to 6 times because the heart does not fully pump the blood out, which
pools in the heart. When the blood pools in the heart, the risk of blood
clots forming is high. Once formed, these blood clots will travel through
the bloodstream into the brain obstructing a blood vessel.
Cardiovascular disease. Several cardiovascular diseases such as:
- Coronary disease: A disease of the arteries that
supply blood to the heart muscle. The arteries become hardened and narrow
because of a plaque build-up; the plaque is a mixture of fatty deposits.
- Peripheral artery disease: A disease where the blood
vessels that carry blood to the leg and arm muscles narrows.
- Carotid artery stenosis: A disease that affects the
carotid arteries from the neck area that supplies the brain with blood.
The carotid arteries become narrow because of fatty deposits build-ups.
- Congestive heart failure: A condition where the heart
cannot pump enough blood to the organs.
- Heart attacks: A medical condition that occurs when
the blood supply to a part of the heart is interrupted.
- Endocarditis: An inflammation of the inner layer
of the heart.
- Other: aortic and mitral valve disease, valve replacement,
dilated cardiomyopathy (an enlarged
heart) can also increase the risk for stroke.
Diabetes. Diabetes is a medical condition where the body either
does not produce enough insulin, or the insulin is not properly used.
This disease is another major cause of stroke because the body can't properly
process sugar (the basic fuel of the body's cells) and fats. Diabetes
also leads to other medical complications such as high blood pressure,
high cholesterol, atherosclerosis, and obesity or excessive weight. Diabetes
interferes with the body's ability to break down blood clots, which leads
to an increased risk of ischemic strokes. In general, those that suffer
from diabetes have a 2 to 4 times the risk of stroke than the non-diabetic
population.
High cholesterol. Cholesterol is a waxy, fat-like substance produced
by the liver and is used in different functions essential for the body.
If present in high amounts, cholesterol builds up in the veins and clogs
them (a condition called atherosclerosis). The build-up
of plaque inside the artery causes the walls to lose their elasticity
and become weak and hard.
2. Lifestyle choices that
can be changed:
- Smoking: Those that smoke have a higher risk of having a stroke
than the non-smoking population. Smoking damages the blood vessel walls,
contributes to plaque build-up in the arteries, makes the heart work
harder, and increases the heart rate and blood pressure. The carbon
monoxide in cigarettes smoke replaces the oxygen in the blood and decreases
the amount of oxygen received by the arteries' walls, tissues and organs.
- Alcohol use: Excessive amounts of alcohol can lead to high
blood pressure. Drinking more than 2 standard alcoholic drinks per day
can increase the risk of stroke by 50 percent.
- Drug use: Drugs such as cocaine, amphetamines, and heroin,
have been linked to an increased risk of stroke.
- Obesity or excessive weight. Being obese or overweight increases
the risk of high blood pressure, high cholesterol, diabetes, heart disease,
which all increase the risk for stroke.
II. Uncontrollable factors
include:
- Age: Stroke risk increases as a person ages. The incident of
stroke increases significantly with age in both women and men. After
the age of 55, the risk of strokes doubles every 10 years.
- Gender: For the entire elderly population, the chances of having
a stroke should be a major concern. However, as to whether women are
more at risk than men, or the risk is equal, the available research
is unclear. The gender difference is obvious in the stroke incident
for age groups. The stroke risk is higher in women older than 85 and
in men 84 or younger. The risk of stroke is also high in middle age
women. In younger people, stroke affects women and men in the same way.
However, women have a higher risk than men to suffer from a hemorrhagic
stroke.
- Race: For the African-American population, the risk of stroke
is two times higher than Caucasians. Hispanics and Asian/Pacific Islanders
also face a higher risk of stroke than Caucasians.
- Family history: Those that have family members that had a stroke
also face a higher risk.
- Previous stroke: The risk of stroke increases if the person
suffered previously from a stroke. Statistics show that a previous stroke
or transient ischemic attack increases the risk of a future stroke in
the next 5 years by 25 to 40 percent.
Article by Kona Vishnu, MS
Medical Writer,
OmniMedicalSearch.com
Stroke Bibliography |
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