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Heart attacks are generally caused by severe
coronary artery disease. Most heart attacks are caused by blood
clots that form on atherosclerotic plaque. This blocks a coronary
artery from supplying oxygen-rich blood to part of the heart. A
number of major and contributing risk factors increase the risk of
developing coronary artery disease. Some of these can be changed and
some cannot. People with more risk factors are more likely to
develop coronary artery disease.
Major risk factors
Major risk factors significantly increase the risk of coronary
artery disease. Those which cannot be changed are:
Heredity. People whose parents have coronary artery disease are more
likely to develop it. African Americans are also at increased risk,
due to their higher rate of severe hypertension than whites.
Sex. Men under the age of 60 years of age are more likely to have
heart attacks than women of the same age.
Age. Men over the age of 45 and women over the age of 55 are
considered at risk. Older people (those over 65) are more likely to
die of a heart attack. Older women are twice as likely to die within
a few weeks of a heart attack as a man. This may be because of their
other co-existing medical problems.
Major risk factors which can be changed are:
Smoking. Smoking greatly increases both the chance of developing
coronary artery disease and the change of dying from it. Smokers
have two to four times the risk of non-smokers of sudden cardiac
death and are more than twice as likely to have a heart attack. They
are also more likely to die within an hour of a heart attack. Second-hand
smoke may also increase risk.
High cholesterol. Cholesterol is a soft, waxy substance that is
produced by the body, as well as obtained from eating foods such as
meat, eggs, and other animal products. Cholesterol level is affected
by age, sex, heredity, and diet. Risk of developing coronary artery
disease increases as blood cholesterol levels increase. When
combined with other factors, the risk is even greater. Total
cholesterol of 240 mg/dL and over poses a high risk, and 200–239 mg/dL
a borderline high risk. In LDL cholesterol, high risk starts at
130–159 mg/dL, depending on other risk factors. HDL (healthy
cholesterol) can lower or raise the coronary risk also.
High blood pressure. High blood pressure makes the heart work harder,
and over time, weakens it. It increases the risk of heart attack,
stroke, kidney failure, and congestive heart failure. A blood
pressure of 140 over 90 or above is considered high. As the numbers
increase, high blood pressure goes from Stage 1 (mild) to Stage 4 (very
severe). When combined with obesity, smoking, high cholesterol, or
diabetes, the risk of heart attack or stroke increases several
times.
Lack of physical activity. This increases the risk of coronary
artery disease. Even modest physical activity is beneficial if done
regularly.
Contributing risk factors
Contributing risk factors have been linked to coronary artery
disease, but their significance and prevalence are not known yet.
Contributing risk factors are:
Diabetes mellitus. The risk of developing coronary artery disease is
seriously increased for diabetics. More than 80% of diabetics die of
some type of heart or blood vessel disease.
Obesity. Excess weight increases the strain on the heart and
increases the risk of developing coronary artery disease, even if no
other risk factors are present. Obesity increases both blood
pressure and blood cholesterol, and can lead to diabetes.
Stress and anger. Some scientists believe that stress and anger can
contribute to the development of coronary artery disease. Stress,
the mental and physical reaction to life's irritations and
challenges, increases the heart rate and blood pressure, and can
injure the lining of the arteries. Evidence shows that anger
increases the risk of dying from heart disease and more than doubles
the risk of having a heart attack right after an episode of anger. |
