NSW Quit - Fact Sheet 12

SMOKING & HEART DISEASE

For most people, lung cancer is the disease most commonly associated with smoking. However, it is actually diseases of the cardiovascular system which are the major cause of death for smokers. Smoking is believed to be the most important preventable risk factor for coronary heart disease (CHD) in Australia.

Of 23,000 deaths due to smoking in Australia each year, more than 8,000 (36%) are from smoking-attributable heart attacks, according to the National Heart Foundation. The association is even stronger in younger adults, with smoking implicated is as many as three out of every four deaths from heart attack in this group.

HOW SMOKING AFFECTS THE CARDIOVASCULAR SYSTEM

Of the 4,000 or so chemical substances identified in cigarette smoke, the most damaging to the cardiovascular system are nicotine and carbon monoxide. According to the National Heart Foundation, these two chemicals exert both immediate and long-term effects.

Nicotine results in immediate and transient increases in blood pressure, heart rate, cardiac output and coronary blood flow, and causes narrowing of arteries in the legs. These effects on the cardiovascular system can be fatal if severe atherosclerosis (narrowing of blood vessels and hardening of artery walls) is present.

Carbon monoxide binds to haemoglobin (which normally carries oxygen from the lungs via the bloodstream), thus reducing the amount of oxygen delivered to the tissues.

There is a cumulative effect of these assaults on the cardiovascular system over time. There is some evidence that smoking may repeatedly damage the lining of blood vessels and encourage clot formation. This contributes to the development of atherosclerosis which can lead to raised blood pressure and increased clot formation.

CARDIOVASCULAR DISEASES RELATED TO SMOKING

The National Heart Foundation (NHF) outlines the following diseases and their relationship to smoking.

Coronary heart disease (CHD) kills about one in three Australians. The death rate for smokers is about 70% higher than for non-smokers. For very heavy smokers, the risk is 200% higher. The NHF notes that smoking increases a person's coronary age by about 10 years.

About half of all deaths from CHD occur without warning and are known as sudden death. Smokers run three times the risk of sudden death compared with non-smokers. One of the causes of sudden death is ventricular fibrillation (or disruption to the heart's electrical system) which prevents the heart beating effectively.

Aortic aneurysm is a ballooning of the aortic artery wall at the point of the artery weakened by the pressure from blood flow. This aneurysm can rupture, with life-threatening consequences. For smokers, the risk of a ruptured aortic aneurysm is up to eight times that for non-smokers.

Stroke or cerebrovascular accident, is an interruption of blood supply to the brain, which can result from atherosclerosis or high blood pressure. Smoking is a contributing factor, especially in younger people.

Peripheral vascular disease is a disease of the blood vessels in the legs caused by atherosclerosis. Cigarette smoking is the most important risk factor for this disease, which is rarely found in non-smokers. Peripheral vascular disease can lead to painful leg ulcers which are slow to heal and eventually leads to gangrene, resulting in amputation of the limb.

High blood pressure (hypertension) combined with smoking greatly increases the risk of coronary heart disease. Malignant hypertension is more common in smokers than non-smokers.

Women who take the contraceptive pill and who smoke, face up to 39 times greater risk of having either a heart attach or stroke than women who neither smoke nor take the pill.

PASSIVE SMOKING & HEART DISEASE

The National Heart Foundation notes that a recent review of the literature identified 13 studies indicating a 30% increase in the risk of heart attach for the spouses or partners of smokers.

They note that exposure to environmental tobacco smoke (ETS) causes a marked increase in platelet stickiness in non-smokers, which may contribute to coronary artery blockage.

For those who have heart disease, exposure to ETS exacerbates their problems because of increased absorption of carbon monoxide which compromises the blood's ability to absorb oxygen.

OTHER RISK FACTORS

Apart from smoking, other factors which increase the risk of cardiovascular disease include alcohol consumption, lack of regular exercise and obesity. A combination of these risk factors greatly increases the risk of sickness and death.

The 1989-90 ABS National Health Survey noted a strong association between smoking and drinking alcohol. Only 28% of smokers were not drinkers, according to the survey. In addition, 40% of smokers indicated that they did not partake in any exercise.

THE EFFECT OF SMOKING CESSATION

The 1983 US Surgeon General's Report, which focused on effects of smoking cessation on cardiovascular disease, found evidence of a substantial reduction in death rates from coronary heart disease after smoking cessation. The following table (reproduced from Brunton's publication Nicotine Addiction and Smoking Cessation) indicates the reduction in risk of 10 years after quitting.