心血管病-Preventing Cardiovascular Diseases

What is cardiovascular disease?

Cardiovascular diseases are diseases of the heart (cardiac muscle) or blood vessels (vasculature). However, in practice, when doctors use the term 'cardiovascular disease' they usually mean diseases of the heart or blood vessels that are caused by atheroma.

The rest of this leaflet briefly discusses atheroma, the diseases atheroma can cause, and ways of preventing a build up of atheroma and preventing the diseases it causes.

What is atheroma (atherosclerosis)?

Patches of atheroma are like small fatty lumps that develop within the inside lining of arteries (blood vessels). Atheroma is also known as 'atherosclerosis' and 'hardening of the arteries'. Patches of atheroma are often called 'plaques' of atheroma.

A patch of atheroma makes an artery narrower, which can reduce the blood flow through the artery. Over time, patches of atheroma can become larger and thicker.

Sometimes a patch of atheroma may develop a tiny 'crack' or 'rupture' on the inside surface of the blood vessel. This may trigger a blood clot (thrombosis) to form over the patch of atheroma which may completely block the blood flow. Depending on the artery affected, a blood clot that forms over a patch of atheroma can cause a heart attack, a stroke, or other serious problems.

What are the cardiovascular diseases caused by atheroma?

Heart disease
The term 'heart disease', or 'coronary heart disease', is used for conditions caused by narrowing of one or more of the coronary (heart) arteries by atheroma. The problems this can cause include: angina, heart attack, and heart failure. (It is confusing as there are other heart conditions such as heart valve problems, congenital heart problems, etc. However, these are not usually included when we talk about 'heart disease'.) Heart disease is common in the UK in people over 50.

Cerebrovascular disease - stroke and TIA
Cerebrovascular disease means a disease of the arteries in the brain (cerebrum). The problems this can cause include a stroke and a TIA (transient ischaemic attack). A stroke means that part of the brain is suddenly damaged. The common cause of a stroke is due to an artery in the brain which becomes blocked by a blood clot (thrombus). The blood clot usually forms over some atheroma. A TIA is a disorder caused by temporary lack of blood supply to a part of the brain.

Peripheral vascular disease
Peripheral vascular disease is narrowing due to atheroma affecting arteries other than arteries in the heart or brain. The arteries that take blood to the legs are the most commonly affected.

If you can prevent a build up of atheroma in the arteries, you are less likely to develop the above diseases. If you already have one of the above diseases you may prevent or delay it from getting worse if you prevent further build-up of atheroma.

Risk factors

Everybody has some risk of developing atheroma. However, certain 'risk factors' increase the risk. Risk factors include:

• Lifestyle risk factors that can be prevented or changed:
  • Smoking.
  • Lack of physical activity (a sedentary lifestyle).
  • Obesity.
  • An unhealthy diet.
  • Excess alcohol.
• Treatable or partly treatable risk factors:
  • Hypertension (high blood pressure).
  • High cholesterol blood level.
  • High triglyceride (fat) blood level.
  • Diabetes.
  • Kidney diseases causing diminished kidney function.
• Fixed risk factors - ones that you cannot alter:
  • A strong family history. This means if you have a father or brother who developed heart disease or a stroke before they were 55, or in a mother or sister before they were 65.
  • Being male. 医学全在线www.med126.com
  • An early menopause in women.
  • Age. The older you become, the more likely you are to develop atheroma.
  • Ethnic group. For example, people who live in the UK with ancestry from India, Pakistan, Bangladesh, or Sri Lanka have an increased risk.
  However, if you have a fixed risk factor, you may want to make extra effort to tackle any lifestyle risk factors that can be changed.

Note: Some risk factors are more 'risky' than others. For example, smoking causes a greater risk to health than obesity. Also, risk factors interact. So, if you have two or more risk factors, your health risk is much more increased than if you just have one. For example, a middle aged male smoker who does little physical activity and has a strong family history of heart disease has quite a high risk of developing a cardiovascular disease such as a heart attack or stroke before the age of 60.

Research is looking at some other factors that may be risk factors. For example, high blood levels of apolipoprotein B or homocysteine are being investigated as possible risk factors.

Known risk factors that can be prevented, changed or treated are now discussed further.

Lifestyle risk factors that can be prevented and/or changed

Smoking
Lifetime smoking roughly doubles your risk of developing heart disease. (The chemicals in tobacco get into the bloodstream from the lungs to do the damage to the arteries and other parts of the body.) Your risk of having a stroke, and developing other diseases such as lung cancer, mouth cancer and throat cancer, are also increased. Stopping smoking is often the single most effective thing that you can do to reduce your health risk. The increased risk falls rapidly immediately after stopping smoking (although it may take a few years before the excess risk reduces completely). If you smoke and are having difficulty in stopping, then see your practice nurse for help and advice.

Lack of physical activity - a sedentary lifestyle
People who are physically active have a lower risk of developing cardiovascular diseases compared to inactive people. To gain health benefits you should do at least 30 minutes of moderate physical activity, on most days (at least five days per week).

• 30 minutes in a day is probably the minimum to gain health benefits. However, you do not have to do this all at once. For example, cycling to work and back 15 minutes each way adds up to the total of 30 minutes.
• Moderate physical activity means that you get warm, mildly out of breath, and mildly sweaty. It does not have to be intense. For example: brisk walking, jogging, swimming, cycling, etc. However, some evidence does suggest that the more vigorous the exercise, the better for health - particularly for preventing heart disease.
• On most days. You cannot 'store up' the benefits of physical activity. You need to do it regularly.

Obesity and overweight
On average, if you are obese and reduce your weight by 10%, your chance of dying at any given age is reduced by about 20%. This is mainly because you are less likely to develop cardiovascular diseases, diabetes, or certain cancers. The increased health risk of obesity is most marked when the excess fat is mainly in the abdomen rather than on the hips and thighs. As a rule, a waist measurement of 102cm or above for men (92cm for Asian men) and 88cm or above for women (78cm for Asian women) is a significant health risk.

Diet
Eating healthily helps to control obesity, and lower your cholesterol level. Both of these help to reduce your health risk. Also, there is some evidence that eating oily fish (herring, sardines, mackerel, salmon, kippers, pilchards, fresh tuna, etc) helps to protect against heart disease. It is probably the 'omega-3 fatty acids' in the fish oil that helps to help reduce the build-up of atheroma. Also, fruit and vegetables, as well as being low in fat, also contain 'antioxidants' and vitamins which may help to prevent atheroma building up. Briefly, a healthy diet means:

• AT LEAST five portions, and ideally 7-9 portions, of a variety of fruit and vegetables per day.
• THE BULK OF MOST MEALS should be starch-based foods (such as cereals, wholegrain bread, potatoes, rice, pasta), plus fruit and vegetables.
• NOT MUCH fatty food such as fatty meats, cheeses, full-cream milk, fried food, butter, etc. Use low fat, mono-, or poly-unsaturated spreads.
• INCLUDE 2-3 portions of fish per week. At least one of which should be 'oily'.
• If you eat meat it is best to eat lean meat, or poultry such as chicken.
• If you do fry, choose a vegetable oil such as sunflower, rapeseed or olive oil.
• Try not to add salt to food, limit foods that are salty such as processed foods.

Alcohol
A small amount of alcohol (1-2 units per day) may help to protect you from heart disease. One unit is in about half a pint of normal strength beer, or two thirds of a small glass of wine, or one small pub measure of spirits. However, too much alcohol can be harmful. Men should drink no more than 21 units per week (and no more than four units in any one day). Women should drink no more than 14 units per week (and no more than three units in any one day).

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