Hypertension or increased blood pressure can affect the coronary arteries, brain, eyes and even the kidneys. High blood pressure has extra strain on the heart and the arteries supplying blood to the body parts .In a majority of the people, hypertension does not produce any symptoms. These people are ignorant about the presence of this disease. Hypertension is rightly called the “silent killer”.
Diabetes Mellitus:

Coronary artery disease is common in diabetics. Diabetes can affect all parts of the body but mainly the vascular system.
Diabetics have an increased level of triglycerides and a low level of HDL (good cholesterol). The LDL (bad cholesterol) is more easily oxidized, which makes a diabetic person more prone to arterial blockages. Diabetes leads to a lot of complications important being atherosclerosis. Increased glucose level affects aortic wall metabolism.

Stress And Risk Personality:
Stress makes the body to absorb more of cholesterol and also causes a decrease in the level of HDL. Excessive stress can lead to increase in blood pressure, heart rate, cholesterol in the blood, concentration of fat in the blood, deposition of fat and cholesterol in the arteries, and spasm of coronary and other arteries. Stress can influence the body in such a manner that even in the absence of other risk factors; a person can be prone to coronary heart disease. Type A personality people are more prone to constant anxiety and suffer from the effects of stress.

Smokers are more prone to develop heart disease than non-smokers. Nicotine in a cigarette is a nerve poison which causes the heart to beat faster and less efficiently. Carbon monoxide inhaled deprives the heart muscle of oxygen and directly poisons the heart muscles. As a result, not only does the heart beat less efficiently, it but also has a lesser capacity for recovery in the event of a heart attack.

It is believed that a high level of cholesterol in the body leads to blockage in the coronary arteries. LDL is the form of cholesterol that delivers fat to all the body tissues. Even then LDL is called the bad cholesterol. It is bad cholesterol when it is in oxidized form.HDL is important for the body as it protects those who have an increased level of cholesterol from atherosclerosis.

Cholesterol levels below 200 mg/dl indicate a relatively low risk of heart disease, but the risk doubles for people with cholesterol levels over 240 mg/dl. Blood cholesterol levels depend on age, gender, heredity, diet, and weight. Overweight or obese people are more likely to have cholesterol elevations or abnormal values for other blood fats.In addition to cholesterol, abnormal triglyceride and HDL-cholesterol levels can increase the risk of heart disease.These levels are often affected by excess body weight, and should be tested in people who are overweight or obese.It is possible to have a normal cholesterol level, but abnormal triglyceride and HDL levels. Triglyceride levels should be below 150 mg/dl, while HDL (often called the good cholesterol) should be 35 mg/dl or higher.

Obesity is defined as the condition of being overweight, with excessive accumulation of fat in various parts of the body. Obese people have more chances of having high blood pressure and diabetes which leads to blockages. It also forces the heart and circulatory system to work harder.
Obesity may accelerate atherosclerosis (a condition in which deposits of fatty substances form inside an artery and obstruct the flow of blood) and its effect is more prominent before the age of 50. Overweight is a significant risk factor for angina because the frequency of angina is five times higher among obese patients than among persons with normal weight..

Lack of Exercise (Sedentary lifestyle):
Exercise is as important as breathing, especially for those prone to heart disease.Increased chances of coronary heart disease are related to lack of physical exercise, and sedentary occupation.Lack of exercise also precipitates the onset of other diseases like diabetes, hypertension, obesity and joint disease, etc., and contributes to very low fitness and flexibility levels.

Social isolation leads to stressful situation.It is simple to believe that feeling of being abandoned does not affect the occurrence of disease and is not a contributory factor in causation of disease.But this belief can’t stand the test of times as humans have feelings.Being neglected or isolated or dejected does bring trouble if not sooner. It is easier for doctors to prescribe drugs on pathological level but it becomes a challenge when dealing with changes in emotional level.How easily we can recognize the feeling of anger but at the same time we over look towards the feeling of isolation.
It is important for us to interact with each other, to socialize, to participate in group or family discussions, to share our innermost feelings and secrets.This opening up of heart will remove the feeling of isolation and will help not only in preventing heart disease but also in reversing it.
Isolation brings on stress, sickness and later lead on to some organic changes in our body.Feelings like friendliness, love, compassion, companionship gives us happiness, peace, calmness and it removes negative emotions.

Blood Factors:
At present there is no formal recommendation for changing the levels of these substances.A toxic amino acid derived from animal protein called homocysteine also damages the arteries. One of the clotting factors, factor 7 has shown to increase the chances of coronary artery disease. An increased level of Fibrinogen is another risk factor for development of cardiovascular disease as this blood component helps in promoting blood clotting. When the level of PAI-1 increases, a decrease in fibrinolytic activity happens, this causes the blood to clot more easily.

Lack of Antioxidants:
Antioxidants help in reducing the bad effects of LDL and lipoprotein which have a significant detrimental effect on the coronary arteries.

Inflammations and Infections:
Though certain studies show it to be so, it has yet to be proven that chronic inflammation is one of the risk factors.