Heart Disease

Risk factors

Large population studies show that some people are at greater risk of heart and blood vessel disease or cardiovascular disease (CVD) than others, even taking age and ethnic background into account.

The risk to a population must be distinguished from the risk to an individual.  While a person's chance of  developing CVD can be calculated from known risk  factors, it is a statistical exercise only. It does not necessarily mean they will develop heart disease.

Ongoing research is shedding light on this complex relationship between risk factors. But our best advice at present is to reduce your risk as much as possible.

What are the risk factors

The first three of the major risk factors are outside the individual's control and cannot be modified.  The others can be reduced or eliminated by change in lifestyle or by medical treatment.

Major risk factors—Non modifiable

· Family history of heart disease

· Sex = male

· Age

Major risk factors—Modifiable

· Smoking

· Raised blood cholesterol

· High blood pressure

· Physical inactivity

· Obesity

Other risk factors

· Diabetes

· Contraceptive pill

· Raised uric acid levels

· Left ventricular hypertrophy

· Alcohol

· Stress

· Raised levels of homocysteine and low levels of B vitamins

The major risk factors

Family history

People with a history of heart disease in their families are more likely to develop heart disease themselves. The risk doubles if your parents died from CVD before the age of 60. Knowing this risk factor means that particular attention should be given to those risk factors which are modifiable.

Sex and age

As age increases for both men and women a large increase in death rates from heart disease is seen. The death rate in men is higher than in women up to the age of 50.  In later years the difference diminishes. The differences are thought to be hormone-related. Some female hormones are thought to protect against heart disease until menopause.

Cigarette smoking

This is the most important of the modifiable risk factors.  Heavy smoking doubles the risk of heart attack and stroke.  Smokers are also at higher risk of sudden cardiac death.

The good news for ex-smokers, is that this extra risk decreases quickly and over time is almost the same as for those who have never smoked. 

Raised blood cholesterol

Raised blood cholesterol is an important risk for heart disease.  Generally speaking, the higher the cholesterol level, the higher the risk.  More than half the Australian population have undesirably high cholesterol levels.  The Heart Foundation recommends for individuals to keep their cholesterol below 5.0 mmol/L.  Determining the levels of different types of cholesterol ie. HDL and LDL, is also very important also in assessing  risk. Elevated triglycerides are less of a problem but may have some significance. See “Cholesterol and other blood fats”

High blood pressure

There is a close relationship between high blood pressure (hypertension) and the development of cardiovascular disease. The risk of heart disease, stroke and heart failure  increases with blood pressure.  Even mildly elevated blood pressure carries a significantly higher risk.

About one in six Australians have high blood pressure, often without knowing it because usually there are no early symptoms.  Once diagnosed, however, high blood pressure can be effectively controlled with drugs and lifestyle changes. 

Physical inactivity

There is strong link between inactivity and increased risk of developing CVD (cardiovascular disease).  The beneficial effect of exercise has been shown to be independent of its effect on other risk factors. It also contributes substantially by modifying other risk factors such as being overweight, high blood pressure and blood cholesterol levels.

In Australia approximately 50% of people do not do enough physical activity to improve their health and, of those, about 13% do no exercise at all.  It has also been shown that at even light exercise levels people gain beneficial effects.  Simply by walking briskly for 30 minutes on most days of the week will give  protective
effects. 

Obesity and overweight

These are thought to directly increase the risk of heart disease.  They also contribute to high blood pressure, high blood fat levels and diabetes, each a risk factor in its own right. 

Diabetes

Diabetes is characterised by raised blood sugar levels and is a significant risk factor for cardiovascular disease.  Optimal blood sugar control will reduce risk.

Contraceptive Pill

The combination of the contraceptive pill with other factors such as smoking, age , diabetes, high cholesterol or family history can significantly  increase risk.

Raised Uric Acid

Raised uric acid levels and/or gout sometimes precede heart disease.  The full implications of this, however, are not clear.

Homocysteine

High levels of homocysteine (a by product of protein metabolism) have been independently associated with increasing risk for coronary heart disease. Eating a diet high fruits and vegetables, breads and cereals, with adequate, but not excessive levels of protein rich foods will help keep homocysteine and B vitamin levels normal.

 Other factors

Alcohol

Alcohol can markedly affect some of the major risk factors.  Even moderate alcohol intake will raise the blood pressure of susceptible people.  Alcohol can alter blood fat ratios, and excess intake can contribute  to  weight problems.

However, moderate intake (up to 2 alcoholic drinks per day for both men and women) may give some protection against heart disease, perhaps by increasing the "good" HDL-cholesterol.  But the key point is moderation.

Stress

Although it is popularly believed that stress can cause heart attacks and that reducing it will lower the risk of heart attack, there is not enough evidence to support this.  Acutely stressful events may also precipitate life threatening arrhythmias.  This may be important, particularly in established heart disease.

Interaction of risk factors

Most of the major risk factors contribute independently to risk, but as risk factors are combined the risk can be greatly increased.

More than half the decline in cardiac deaths in the past 20 years are probably due to a reduction in risk factors.  Prevention now centre’s on further modifying them.

For more information

Wesley Corporate Health

Level 2 / 46 Edward Street

Brisbane  Qld  4000

Phone:  07 3234 2600

Email: wellness@weshealth.com.au

Disclaimer

This Fact Sheet is provided for your information only and does not replace qualified medical advice. The
information provided may not apply to every person or all situations. A medical practitioner should be consulted for all treatment and medication.