An aortic aneurysm can rupture (dissecting aneurysm) and cause massive blood loss, circulatory shock and rapid death

Family history Age (65 and over) Male gender Tobacco smoking and Passive smoking High blood pressure High cholesterol levels in the blood Poor diet that is high in saturated fats Diabetes mellitus Overweight and Obesity Lack of physical activity and exercise There are many factors which increase the risk of coronary heart disease; some of these risks are controllable, e.g. diet, whereas others are unavoidable and are based on genetics and advancing age Risk factors include:

The risk of coronary heart disease is directly related to blood cholesterol levels Cholesterol is a lipid (steroid) which is carried through the bloodstream in combination with proteins; the combined products are lipoproteins Cholesterol structure

Cholesterol is manufactured by the liver The meat and dairy products in our diet are rich in cholesterol Cholesterol is transported in the blood in combination with proteins - lipoproteins

There are two different types of cholesterol: Low-density lipoproteins LDLs: known as ‘bad cholesterol’ as they contain high levels of cholesterol High-density lipoproteins HDLs: known as ‘good cholesterol’ as they contain low levels of cholesterol, and are considered to provide protection against heart disease; HDLs help remove LDLs from arteries Cholesterol levels are measured in millimols (mmol) per litre of blood The British Heart Foundation suggests a cholesterol target of less than 5.0 mmol/l; the average blood cholesterol levels in England for men is around 5.5 mmol/l and for women 5.6 mmol/l (high by international standards)

Source: Joint Health Surveys Unit (2004): Discuss the graph

Recently it has been shown that the risk of heart disease depends not on total cholesterol level, but on the ratio of HDLs to LDLs in the blood Around 20% of total cholesterol is carried in the bloodstream as HDL and about 80% of cholesterol as LDL As the ratio of HDL cholesterol to LDL cholesterol increases, the risk of atherosclerosis decreases (LDL levels under 3 mmol/l are considered to be healthy) Eating less saturated fat and more fibrous foods can encourage a healthy HDL/LDL ratio; a diet high in saturated fats encourages the liver to produce more LDL

The risk of Coronary Heart Disease is directly related to both the systolic and diastolic blood pressure levels Blood pressure varies naturally, and hypertension is generally defined as a chronic elevation of diastolic pressure over 90 mmHg or systolic pressure over 140 mmHg The 2004 British Hypertension Society guidelines recommend that drug treatment should be considered for individuals with blood pressures of 140/90 mmHg and over In the United Kingdom, blood pressure levels are high; in England, 34% of men and 30% of women have raised blood pressure (above 140/90 mmHg)

Hypertension can remain untreated for years due to a lack of easily recognised symptoms Raised blood pressure causes irreversible damage to the cardiovascular system and other organs Raised arterial pressure increases the workload on the heart and increases the risk of myocardial infarction Hypertension stresses the arterial walls and increases the thickness of the muscle layer; as the arterial lumen narrows, blood pressure increases further Hypertension can damage the endothelial lining of arteries predisposing them to the development of atherosclerosis

Obesity Stress Smoking Excessive alcohol consumption Diet – high salt intake; salt lowers the water potential of the blood and more fluid is absorbed into the blood vessels – the increased blood volume raises the blood pressure Genetic predisposition (familial hypertension) Risk factors for hypertension include:

Smoking has been identified as the single greatest cause of preventable illness and premature death, with cigarette smokers having a four-fold increased risk of developing coronary heart disease than non-smokers Carbon monoxide in tobacco smoke Nicotine in tobacco smoke The effect of tobacco smoke on cholesterol levels; smoking has been shown to increase blood cholesterol levels The increased risk of heart disease is thought to be associated with:

Haemoglobin has a higher affinity for carbon monoxide than oxygen; increased blood carbon monoxide levels reduces the amount of oxygen delivered to cells; reduced oxygen delivery is thought to accelerate the changes that occur in damaged arterial linings Nicotine is a vasoconstrictor; when the lumens of arteries narrow, blood pressure increases and contributes to the risk of cardiovascular disease

Physical activity lowers the risk of coronary heart disease It is recommended that adults should aim for at least 30 minutes of moderate activity on five or more days of the week; a recent health survey for England shows that only 37% of men and 24% of women are active at this level Explain how physical activity reduces the risk of coronary heart disease