Read this article then make a summary table to show the causes of Heart Disease.  You must include 5 causes and an explanation of the effects of each.

 Coronary Heart Disease
(this article shows good use of references and bibliography,
useful for extended essays)

What is Coronary Heart Disease (CHD)?

CHD has two principal forms - angina and heart attacks.  Both occur because the arteries carrying blood to the heart muscle become blocked or narrowed, usually by a deposit of fatty substances, a process known as arteriosclerosis.  Angina is a severe pain in the chest brought on by exertion and relieved by rest.  A heart attack is due to obstruction of a coronary artery either as a result of arteriosclerosis or a blood clot.  Part of the heart muscle is deprived of oxygen and dies. (Roberts, Reiss and  Mange, 2000)

Risk factors for Coronary Heart Disease (CHD)

Cigarette smoking, raised blood cholesterol and high blood pressure are the most firmly established, non-hereditary risk factors leading to CHD.   Even light smokers are at increased risk of CHD. Other factors include being male, age, having close relative who have had heart attacks being overweight, taking to little exercise, having high blood pressure and eating too much salt or saturated fat or too little fibre

Cigarette smoking is the "most important of the known modifiable risk factors for CHD".  A cigarette smoker has two to three times the risk of having a heart attack than a non-smoker.  Smoking: tends to increase blood cholesterol levels.  Cigarette smokers also have raised fibrinogen levels and platelet counts, which make the blood stickier.  All these factors make smokers more at risk of atherosclerotic disease, where blood flows less easily through rigid and narrowed arteries.  The blood is more likely to form a sudden blockage of an artery leading to a fatal heart attack, a stroke or gangrene.

At least 80% of heart attacks in men under 45 are thought to be due to cigarette smoking. (Townsend, JL and Meade, TW. 1979) At this age, heavy smokers have 10 to 15 times the rate of fatal heart attacks of non-smokers.  A women who smoked 1-4 cigarettes a day had a 2.5-fold increased risk of fatal coronary heart disease. (Bartecchi CE, et al. 1994).

Saturated Fats: The relation between fat intake and the risk of coronary heart disease is not fully understood, however it does seem clear though that a high level of saturated fats and cholesterol in the diet is associated with an increased risk of coronary heart disease. ( Roberts, Reiss and Mange, 2000)

Age: the risk of coronary arteriosclerosis increases with age, but evidence suggests that the condition may start to develop very early in life. About four out of five people who die of coronary heart disease are age 65+. At older ages, women who have heart attacks are more likely than men to die from them within a few weeks.

Sex: Women before menopause rarely suffer from heart disease (the hormone oestrogen present in women appears to protect them.) Coronary heat disease mainly afflicts adult males and manifests itself in middle-age (45-55 years old).

Diet: individuals with hereditary high levels of blood cholesterol are more prone to develop coronary heart disease.  The risk of coronary heart disease rises as blood cholesterol levels increase. When other risk factors (such as high blood pressure and tobacco smoke) are present, this risk increases even more. A person's cholesterol level is also affected by age, sex and heredity.

High blood pressure: increases the heart's workload, causing the heart to enlarge and weaken over time. It also increases the risk of stroke, heart attack, kidney failure and congestive heart failure.

Weight: People who have excess body fat - especially if a lot of it is in the waist area - are more likely to develop heart disease and stroke even if they have no other risk factors. Excess weight increases the strain on the heart, raises blood pressure and blood cholesterol and triglyceride levels. It can also make diabetes more likely to develop. Heredity: coronary heart disease is much more common in some families than in others. As DNA determines the sizes of the arteries themselves it is probable that characteristics of the heart are passed on to offspring.

Lack of exercise: regular exercise aids a healthy circulation, and the physically inactive are more at risk from heart disease

Other diseases: diabetes and high blood pressure increase the risk of coronary disease.  Diabetes seriously increases the risk, even when glucose levels are under control, diabetes greatly increases the risk of heart disease and stroke.

Socio-economic disadvantage: poor housing and little education are strong indicators of high coronary mortality and more strongly affects those in the lower social levels; as nations become prosperous coronary heart disease becomes less of a problem for the well educated classes.

Psychological and personality factors: sleep disturbances and stress are predictors of angina, infraction and death due to heart attacks.

Birth control pills: higher doses of oestrogen and progesterone, increase a woman's risk of heart disease and stroke, especially in older women who smoked heavily. Newer, lower-dose oral contraceptives carry a much lower risk of cardiovascular disease.
If a woman taking oral contraceptives has other risk factors (and especially if she smokes), her risk of developing blood clots and having a heart attack goes up. It rises even more after age 35.

Clustering of Risk Factors

The tendency of risk factors to cluster in a single individual is being increasingly recognized. 

When high blood pressure exists with obesity, smoking, high blood cholesterol levels or diabetes, the risk of heart attack or stroke increases several times.

Obesity and physical inactivity contribute importantly to the development of multiple risk factors in the American population; this clustering of multiple metabolic risk factors is called the metabolic syndrome. (Grundy SM. Small LDL,1997)   Risk will be further accentuated in smokers with several metabolic risk factors. There is an increasing need to identify persons with multiple risk factors and, because of their high risk, to initiate management directed at all risk factors. (C J Clegg and D G Maclean,1994) AND (http://www.ash.org).

Bibliography

Books

Michael Roberts, Michael Reiss and Grace Mange, Advanced biology 2000; page 24
Doll, R and Peto, R. Mortality in relation to smoking. Br Med J. 1976.
Townsend, JL and Meade, TW. J Epidemiol Health 1979; pages 33: 243-247)
C J Clegg with D G Maclean, Advanced Biology principles and applications 1994, page 361
Grundy SM. Small LDL, atherogenic dyslipidemia, and the metabolic syndrome. Circulation. 1997; 95:1-4.

Journals

US DHHS The health benefits of smoking cessation - a report of the Surgeon General, 1990.
Bartecchi CE, et al. New England Journal of Medicine 1994; pages 330: 907-912

Websites

http://www.americanheart.org/risk factors and coronary heart disease.htm
http://www.ash.org/