Coronary heart disease (CHD), also called coronary artery disease or arteriosclerotic heart disease, is the leading cause of death in the United States for men and women. It accounts for approximately 1 of every 5 deaths. According to the American Heart Association, about every 29 seconds someone in the US suffers from a CHD-related event, and about every minute someone dies from such event.
Approximately 13.9 million adults (7.1 million men and 6.8 million women) have a history of myocardial infarction (MI), angina, or both, and these figures do not include patients with clinically silent disease. Studies indicate that 25% of men and 38% of women will die within 1 year after having recognized MI In the United States, a coronary event occurs every 29 seconds and an MI occurs every minute.
The incidence of coronary heart disease is increased in the presence of certain biochemical, physiologic, and environmental factors, known as risk factors. The well established risk factors are high blood pressure, dyslipidemia/high blood cholesterol, tobacco use/cigarette smoking and diabetes mellitus. Other factors that may increase or affect the risk for heart attack are obesity, a sedentary life-style, an aggressive response to stress, and certain drugs.
Some of the most common risk factors that can be changed or modified include obesity, smoking, high cholesterol, hypertension, diabetes, excessive alcohol intake, stress, and a lack of physical activity. Other factors such as age, gender (male) and heredity or family history of CHD cannot be changed or altered. Age and family history are also considered major risk factors. Although these factors cannot be changed they should be looked at carefully. People affected by these risk factors should be even more on the observant to protect themselves against coronary heart disease.
The presence of one or more of these factors in an individual increases the possibility that a person will suffer from coronary heart disease and its complications. It is also suggested that removal or modification of the risk factors in a population will diminish the incidence of developing coronary heart disease. The succeeding paragraphs will present a brief discussion on some of the risk factors of coronary heart disease.
Obesity or being overweight has many negative side affects that could in turn directly increase a person’s chance for developing a coronary heart disease. It is established that an overweight person even without any other risk factors for CHD is at a higher risk for a heart attack or stroke. Obesity also increases the workload of the heart (increased oxygen delivery for fat metabolism), increases blood pressure, increases cholesterol, and increases a persons risk for developing diabetes mellitus. Actually, all of the potential side effects of obesity are also risk factors for developing coronary heart disease.
Hypertension or high blood pressure means that the mean arterial pressure is greater than the upper range of the accepted normal measure. High blood pressure places constant stress on the heart and as a result the heart becomes thicker and stiffer. Excess workload on the heart in hypertension leads to early heart failure and coronary heart disease, often causing death as a result of a heart attack. High blood pressure mixed with obesity, smoking, high blood cholesterol levels or diabetes mellitus increases the risk of heart attack or stroke by several times.
Dyslipidemia refers to abnormal levels of total cholesterol, low density lipoprotein (LDL) cholesterol, and high density lipoprotein (HDL) cholesterol. Cholesterol is present in the diet of all people, and it can be absorbed slowly from the gastrointestinal tract into the intestinal lymph. The body has two main types of cholesterol, HDL/good and LDL/bad. The problem arises when there is too much cholesterol floating around in the body. High blood cholesterol is a major risk factor. Desirable levels of LDL are those less than 130 mg/dL. HDL cholesterol is protective at levels of 60 mg/dL or more and causes major risk if levels fall below 35 mg/dL (Ganong, 2001). Any cholesterol above 200 mg/dl (for total body cholesterol, HDL + LDL) is considered a moderate to high risk factor for coronary heart disease. An estimated 96.8 million persons (51%) in the United States have total cholesterol levels greater than 200 mg/dL and 37.7 million persons (20%) have levels greater than 240 mg/dL. A person’s cholesterol level is also affected by age, sex, heredity and diet.
In some people who have genetic predisposition to coronary heart disease or in people who eat excessive quantities of cholesterol and other fatty substances, large quantities of cholesterol gradually become deposited beneath the endothelium at many points in arteries throughout the body. Gradually these areas of deposit are invaded by fibrous tissue and frequently become calcified. The net result is the development of atherosclerotic plaques that protrude into the vessel lumens and either block or partially block the flow of blood to the heart .
Diabetes mellitus dramatically increases the risk for heart disease even when a persons blood glucose levels are well maintained. About 75-80% of all diabetics die of some type of heart or blood vessel disease. Smoking and physical inactivity are two almost obvious risk factors. Consistent moderate to intense physical activity and not smoking will reduce a person’s risk factors. In fact, smokers are four times as likely to die of a sudden heart attack then are non-smokers.
For years, the American Heart Association has recommended 30-60 minutes of aerobic exercise three to four times per week to promote cardiovascular fitness. This has been shown to help a person loose or maintain weight, lower blood pressure, increase their HDL (good) cholesterol and lower their LDL (bad) cholesterol. Such activities could include aerobics, jogging, running, swimming, and sports such as tennis, racquetball, soccer, and basketball. Any individual starting a new exercise program with one or more of these risk factors must first get written approval from their doctor.
Advancing age is a CHD risk factor for both men and women because of the inevitable atherosclerosis that comes with the normal aging process. Age 45 years or older in men and 55 years or older in women (or premature menopause without hormone replacement therapy) is associated with greater risk of CHD. The lifetime risk of having coronary heart disease after age 40 is 49% for men and 32% for women. As women get older, the risk increases almost to that of men. Men in their early and mid-adult years are several times more likely to develop atherosclerosis (which can lead to the development of CHD) than women. This suggests that male sex hormones might be atherogenic or, conversely, that female sex hormones might be protective.
Tobacco use or cigarette smoking is, by far, one of the most powerful CHD risk factors. It is currently estimated that 25.9 million men (27.8%) and 23.5 million women (23.3%) in the United States use tobacco products and that 90% of them began before the age of 21. In the United States, tobacco use causes 2 out of 5 cardiovascular-related deaths. Evidence indicates that chronic exposure to environmental tobacco smoke by second-hand smoke or passive smoking also increases the risk of developing coronary heart disease.
Individuals who have strong family histories of CHD are four times as likely to have the disease, compared with those with a weak history. The risk is increased 27 times if three or four risk factors are present – such as DM, hypertension, high cholesterol, and obesity – given a strong familial CHD risk, compared with those with a weak family history of heart disease and no risk factors. If only two risk factors are present in addition to genetic factors, then the risk is increased 19 times, and if no risk factors are present, then the risk for CHD associated with genetic CHD is increased only twofold.
Credit:ivythesis.typepad.com
0 comments:
Post a Comment