Cardiovascular Disease Risk Factors!

The function of the heart is to supply blood to the entire body. The heart in turn gets its nourishment through coronary arteries. It is therefore necessary that coronary arteries are maintained properly throughout the entire body. However, age and certain lifestyle factors injure the blood vessels and coronary arteries and one tends to get diseases associated with cardiovascular system. The term cardiovascular disease includes several diseases such as coronary artery disease, stroke, hypertension, rheumatic heart disease, etc. Focus of this article is on coronary artery disease as this is related with a high rate of hospitalizations and death.
Coronary artery disease (CAD), also called coronary heart disease, is a condition in which plaque builds up inside the coronary arteries. These arteries supply the heart muscle with oxygen-rich blood. When plaque; made up of fat, cholesterol and other substances; builds up in the arteries, the condition is called atherosclerosis. Plaque narrows the arteries and reduces blood flow to your heart muscle. It also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow. When your coronary arteries are narrowed or blocked, oxygen-rich blood can't reach your heart muscle. This can cause angina or a heart attack.

Description of Atherosclerosis

        Adopted from National Institute of Health, U.S. Department of Health & Human Services
Figure A shows a normal artery with normal blood flow. Figure B shows an artery with plaque buildup.


Over time, CAD can weaken the heart muscle and lead to heart failure and arrhythmias. CAD is not due to any single factor but due to several factors and these are called risk factors. The longer the risk factor operates, the greater is the risk of developing the disease. The presence of multiple risk factors has an additive effect. It is also known that CAD is an unavoidable effect of socio-economic development. It is therefore important to know about the risk factors and then focus on factors that can reduce the risk of developing heart disease. In this article we will talk about the major risk factors and focus on ways to reduce them in subsequent articles.



Blood Lipids

Elevated levels of blood lipids (cholesterol and triglycerides) are the major risk factors for heart disease. Cholesterol and other fats can't dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins. There are several kinds, but the most important are Low-Density Lipoprotein (LDL or ‘bad’) and High-Density Lipoprotein (HDL or ‘good’). HDL is the "good" cholesterol which helps keep the LDL (bad) cholesterol from getting lodged into your artery walls. LDL cholesterol is the "bad" cholesterol. When too much of it circulates in the blood, it can clog arteries, increasing your risk of heart attack and stroke. The triglycerides are also important since they influence lipid deposition and clotting mechanisms. Circulating levels of LDL, HDL and Triglycerides are measures of the risk of CAD.

High Blood Pressure

Hypertension is a strong risk factor for cardiac and blood vessel damage. Obesity, particularly fat around the abdomen and excess consumption of alcohol, salt and fat, especially saturated fat, are associated with hypertension. Low intakes of potassium, calcium and magnesium also increase blood pressure. Stress and lack of exercise are other contributing factors.


Blood pressure is typically recorded as two numbers, written as a ratio like this:



Systolic

The top number, which is also the higher of the two numbers, measures the pressure in the arteries when the heart beats (when the heart muscle contracts)
Diastolic

The bottom number, which is also the lower of the two numbers, measures the pressure in the arteries between heartbeats (when the heart muscle is resting between beats and refilling with blood).

Typically more attention is given to the top number (the systolic blood pressure) as a major risk factor for cardiovascular disease for people over 50 years old. In most people, systolic blood pressure rises steadily with age due to increasing stiffness of large arteries, long-term build-up of plaque, and increased incidence of cardiac and vascular disease.



This chart below reflects blood pressure categories defined by the American Heart Association.

Diabetes

Diabetes is a disease wherein blood and urinary glucose increase. Insulin resistance plays an important role in the development of the disease. There are two major types of diabetes.



Type 1 Diabetes:

Type 1 diabetes is a serious condition that occurs when the pancreas makes little or no insulin. Without insulin, the body is unable to take the glucose (blood sugar) it gets from food into cells to fuel the body. So without daily injections of insulin, people with type 1 diabetes won't survive. For that reason, this type of diabetes is also referred to as insulin-dependent diabetes.


Type 2 Diabetes:

Type 2 diabetes is the most common form of diabetes and is associated with obesity. Historically, type 2 diabetes has been diagnosed primarily in middle-aged adults. Today, however, adolescents and young adults are developing type 2 diabetes. This type of diabetes can occur under two different circumstances:



■The pancreas doesn't make enough insulin, or

■The body develops "insulin resistance" and can't make efficient use of the insulin it makes

In diabetes blood lipids are increased and these contribute to premature or accelerated process of cardiovascular disease.

Obesity

Obesity is characterized by an excessive accumulation of body fat through increase in size and number of fat cells. Obese individuals have more body fat and higher levels of blood glucose and cholesterol. For every extra kilogram of fat, one tends to produce 20mg more cholesterol per day. The higher the body weight, the greater is the risk of not only heart disease but also gall stones and cancer. It is therefore necessary to maintain ideal body weight.



Smoking

Nicotine and carbon monoxide in the smoke damage the heart and blood vessels. Nicotine makes the heart beat faster and work harder, therefore more oxygen is required. Carbon monoxide cuts down the oxygen carried by blood vessels. Smoking also increases chronic lung diseases and lung cancer thus reducing the life expectancy in smokers.



Sedentary Habits and Stress

With increasing industrialization and modernization, sedentary lifestyle and stress have become a part and parcel of our lifestyle. Sedentary habits decrease energy expenditure and contribute to obesity and rise in cholesterol levels thus contributing to cardiovascular diseases.
The adage “Prevention is better than cure” is particularly appropriate to chronic heart diseases since cost of treatment far outweighs the cost of disease prevention. A healthy lifestyle that involves regular exercise, a balanced diet and avoidance of over indulgence in foods can prevent heart diseases. In the next article we will highlight the importance of diet on coronary artery diseases.

Originally Published in Valley India Times, February 2011

Sources:
1.National Heart Lung and Blood Institute
2.American Heart Association
3.National Institute of Nutrition, India

Posted in: Heart Health Info