CVD remains the number
one killer of both men and women in the United States.
Almost 60 million Americans have at least one type of
CVD. CVD refers to various diseases affecting your heart
and arteries--including heart disease, stroke,
and high
blood pressure, among others. It was the primary cause
of 953,110 deaths in the United States in 1997 (most recent
statistics available) and was mentioned as a contributing
cause in an additional 452,890 deaths.
The Role of Atherosclerosis
Many people think of heart
attacks and strokes as sudden events, but in fact,
they are the result of a disease process--atherosclerosis--that
has been going on for years. Atherosclerosis is a gradual
buildup of plaque
in your arteries.
This buildup causes arteries to become narrower, which
affects blood flow.
A continual blood flow is vital because blood delivers
the oxygen
and nutrients
each cell in your body needs to survive. As plaque grows,
it causes a partial or total blockage of blood flow
to the area of your body supplied by that artery.
If an artery becomes totally blocked, the cells that
it normally supplies with oxygen and nutrients are damaged
and can even die. In many cases, complete blockage of
a narrowed artery is the result of bleeding into the
plaque or is caused by a blood clot that either forms
at the site or travels from another part of the body.
The most common type of heart attack occurs when the
blocked artery is in your heart--a coronary
artery. A heart attack can also be caused by a temporary
contraction
or spasm
in the artery wall that causes it to narrow. Strokes
occur when the blocked artery is in the head or neck.
Strokes can also be caused by bleeding from an artery
in the brain.
Causes & Risk Factors
Many researchers believe that damage to the artery lining,
which normally is smooth, is the first step in atherosclerosis.
Various substances in your blood are then attracted
to this injury site where they are deposited on the
surface of and inside the artery wall to form plaque.
As plaque grows, the wall thickens and the artery's
inner diameter becomes smaller.
How does this damage occur? The initial damage to artery
walls is commonly caused by:
- higher than normal levels of two fats--low-density
lipoprotein-cholesterol (LDL-cholesterol) and
triglycerides--in your blood
- high blood pressure
- tobacco smoke
- other yet to be defined events
Risk Factors for Heart Disease
|
| Increasing age |
About 80% of people
dying from heart disease are age 65 or older. |
| Male sex |
Men are at higher risk and typically
have their heart attacks at a younger age than women.
The death rate from heart disease increases for
women after they reach menopause. |
| Heredity |
Heart disease often runs in families. |
| Race |
Compared with whites, African Americans,
Mexican Americans, American Indians, native Hawaiians,
and some Asian Americans are at increased risk of
developing heart disease. |
| Smoking |
Smoking is a major risk factor,
causing an estimated 20% of CVD deaths. |
| High LDL-cholesterol |
An elevated blood LDL-cholesterol
level is a major risk factor. |
| High blood pressure |
High blood pressure, which is a
major risk factor, can't be cured but it can be
controlled. |
| Physical inactivity |
Being physically inactive is a major
risk factor for heart disease. |
| Obesity
and overweight |
Having excess body fat, especially
in the waist area, increases your risk of heart
disease. |
| Diabetes |
Diabetes (diabetes mellitus) is
a treatable risk factor for heart disease. |
Adapted from reference 3
Other factors known to contribute to the risk of developing
heart disease include:
- response to stress
- hormonal factors
- use of birth control pills
- excessive use of alcohol
A Word about Lipoproteins
Remember the old saying that oil and water don't mix?
Cholesterol and blood work under a similar premise.
Since cholesterol is a fatty substance, it can't travel
around by itself in your blood, which is primarily water.
Therefore, cholesterol combines with protein to form
a molecule,
called a lipoprotein, which can be carried in your blood.
Two types of lipoproteins most people are familiar with
are low-density lipoprotein-cholesterol (LDL-cholesterol)
and high-density lipoprotein-cholesterol (HDL-cholesterol).
An elevated blood level of LDL-cholesterol, or "bad
cholesterol," increases your risk of heart disease
because these particles contribute to the growth of
plaque. But all LDL-cholesterol isn't alike. LDL-cholesterol
that has been changed in a chemical reaction called
oxidation
is more likely to increase atherosclerosis. This discovery
has led to greater interest in antioxidants,
substances that help reduce oxidation.
HDL-cholesterol is often called "good cholesterol."
Since this lipoprotein removes cholesterol from plaque,
it is considered an "anti-risk" factor. A
higher blood level of HDL-cholesterol helps lower your
risk of heart disease.
References
View cardiovascular
disease references list.
|
