Saturday, April 18, 2009

HEART DISEASE AMONG ASIAN INDIANS

By VASUDEVA R. GOLI, M.D., F.A.C.C.

Dr. Goli is a practicing Cardiologist with Cardiology PC at Birmingham Baptist Princeton Hospital, Birmingham, AL

The intent of this communication is to raise awareness about the high prevalence of heart disease in the Asian Indian community and to make a few suggestions regarding life style modifications for the prevention of heart disease.

Asian Indians around the world have the highest rate of coronary artery disease (CAD); the most common form of heart disease, although half of the population is life long vegetarians. One out of every 10 Asian Indian adults in the United States has CAD, compared to 1 out of every 30 American Whites. When compared to Whites, Blacks, Hispanics, and other Asians, heart disease in Asian Indians is 2 to 4 times higher at all ages and 5 to 10 times higher in the young (under 40 years of age). Heart disease is an “equal opportunity disease”, and you don’t have to be an NRI or a nonvegetarian to qualify for this vulnerability.

According to the latest statistics, 10% of Indians in New Delhi now have CAD, identical to Asian Indians around the world. Heart disease among Asian Indian physicians is three-fold higher compared to the general U.S. population. These rates were even higher in the Kaiser Permanente study which showed four-fold higher hospital admissions for heart disease in Asian Indians when compared to other ethnic groups. Studies also indicated that stress from immigration and cultural adaptation cannot explain this world wide phenomena. The most striking features of CAD in Asian Indians, especially in the young, is in its accelerated course resulting in a very severe, extensive, and rapidly progressive disease.

THE BEGINNING AND SYMPTOMS OF HEART DISEASE:

The most common form of heart disease is coronary artery disease. In coronary artery disease, the blood vessels to the heart become narrowed or blocked by gradual buildup of fat (cholesterol) within the arterial walls, which reduces blood flow to the heart muscle. This buildup is called “atherosclerosis” or hardening of the arteries. Atherosclerosis usually begins in adolescence and progressively advances in the 40s and 50s with no symptoms whatsoever. For about half of the patients who have CAD, the first symptom is cardiac arrest or a heart attack from a sudden closing of an artery. For the other half, chest pain called “angina” appears. It is heaviness in the chest which may travel to the arms, neck or jaw, and is associated with shortness of breath brought on by strenuous physical activity, such as climbing stairs or a brisk walk.

MAJOR RISK FACTORS:

Risk factors that may increase the chance of developing heart disease includes cigarette smoking, high blood pressure, high cholesterol, diabetes, family history of heart disease, low HDL, (Good cholesterol), sedentary life style, and obesity. The presence of one or more of these risks has a major influence on the likelihood of developing heart disease. Some risk factors, such as being a male or having a family history of heart disease, cannot be changed. However, several of the listed risk factors can be changed and can greatly reduce an individual’s risk of heart disease. Conventional risk factors such as high cholesterol, high blood pressure, cigarette smoking, and diabetes have not fully explained the high rate of premature and severe CAD in Asian Indians. It is the feeling of most researchers that the “normal” serum cholesterol and triglyceride levels in the Caucasian population may be high for the Asian Indian population.

CHOLESTEROL AND CORONARY ARTERY DISEASE (CAD):

Elevated serum cholesterol and triglycerides are known to increase the risk of heart disease. There are several subtypes of cholesterol which play a major role. The HDL is called the “good” cholesterol, which actually prevents hardening of the arteries. The LDL cholesterol is widely known as the “bad” cholesterol and is really the “core” of the cholesterol that clogs up the arteries. Recently there has been increasing awareness in the scientific community regarding the increased risk of CAD with increased triglycerides, which are also known as “ugly” cholesterol. A new arrival to the lipid arena is LPa, which deserves the title of the “deadly” cholesterol, and is 10 times more dangerous than LDL, and 15 times more potent than cholesterol in clogging arteries.

A higher serum level of LPa is an independent risk factor for premature CAD and has been reported in Asian Indians. The concentration of LPa is largely genetically determined and minimally infringed by diet and exercise. This “lipid tetrad”, high LDL, low HDL, high triglyceride, and high LPa best explains the malignant atherosclerosis seen in Asian Indians. Total cholesterol of less than 200 mg per deciliter is desirable. A more important measurement would be a total cholesterol/HDL ratio of less than 2.5, and is associated with near immunity from heart attack. A ratio of 4.5 is considered dangerous and increased the likelihood of heart disease. Around 8 to 10% of Asian Indians have diabetes compared to 1% to 2% of White Americans.

PREVENTION OF CAD:

Cooking Oils and Cholesterol: Facts and Myths: Elevated blood cholesterol is the strongest risk factor for heart disease. A dietary excess of saturated fats is the largest contributor. Modification of the diet remains the cornerstone of lowering total cholesterol and LDL. A balanced diet with more fruits, vegetables, and grains, and less sugar and salt should be a life long practice beginning in childhood. With respect to alcoholic beverages, moderation is most important, and one should not exceed more than 1 to 2 drinks per week. Red wine is preferred over other types of alcoholic beverages.

As general rule, 30% of the total daily calories from fat is permitted with 10% of the calories derived from each of the following three fatty acid categories: 1) saturated fatty acid raises cholesterol, 2) polyunsaturated fatty acids lowers cholesterol but also lowers HDL, and 3) Monounsaturated fatty acids lower cholesterol without lowering HDL. Contrary to common belief, the contribution of dietary cholesterol to blood cholesterol is small. Increased saturated fat intake in the diet contributes to the significant elevation of cholesterol in the blood; thus, do not be fooled by the label “cholesterol free”, it does not mean heart healthy. One needs to pay equal attention to saturated fatty acid content in dietary products. Most vegetable cooking oils are low in saturated fat and are “heart healthy”, with the important exception of tropical oils, such as coconut oil and palm oil. These oils are very rich in saturated fats. Although these oils contain no cholesterol, their cholesterol raising potential is similar to or higher than most animal fats. Liberal use of these oils should be discouraged.

FOOD FOR YOUR HEART:

The greatest reduction in blood cholesterol and risk of heart disease is best achieved by lowering intake of saturated fatty acids. This is best accomplished by avoiding butter and ghee, replacing full fat milk with skim milk, by consuming less daily fat, and by adding more fish and chicken (without skin), and fiber rich foods. No more than 2 servings per day of lean meat and shellfish may be used. Most vegetable cooking oils are low in saturated fats and are “heart healthy”. Canola oil and olive oil are especially rich sources of monounsaturated fatty acids. Liberal use of palm oil and coconut oil are discouraged as they are loaded with saturated fatty acids. Daily consumption of fiber and more servings of fruits and vegetables would provide most necessary anti-oxidants and are preferable to vitamin supplements. Anti-oxidants prevent hardening of the arteries.

RECOMMENDATIONS FOR EXERCISE:

Exercise and weight reduction are cornerstones of raising HDL. The best exercise is what can be done year round and lifelong, which varies in different individuals. Brisk walking, jogging, tennis, golf without a cart, gardening, and swimming are all good aerobic exercises. Thirty to forty minutes of exercise per day at least 4-5 days per week year-round is recommended. Higher duration and frequency are mandatory for those who are rich around the abdomen having “spare tire syndrome”.

CONCLUSIONS:

Asian Indians have the highest rate of heart disease of any ethnic group studied to date. Coronary atherosclerosis in this population occurs early and is very severe, extensive, and follows a rapidly progressive course with high mortality. In addition to conventional risk factors, such as high cholesterol, high blood pressure, cigarette smoking, diabetes, and family history, high levels of LPa may also explain the high incidence of heart disease in Asian Indians. Ideally, the prevention of heart disease should begin in childhood, but prevention beginning in middle age is certainly “better than never”. Those with a family history of premature heart disease should aggressively consider lifestyle modifications, including exercise, a low cholesterol diet, and screening for lipid abnormalities.

The ravages of heart disease can be substantially reduced by aggressively attacking all known risk factors. Teenagers should not start cigarette smoking and adults who are smoking should not wait for a cardiac arrest to quit. A diet high in fish, fiber, fresh fruit, and vegetables rich in natural anti-oxidants; a diet low in total saturated fats and calories, adjusted to prevent obesity and maintain ideal body weight, should be started as early as childhood. In addition to dietary modifications, exercise should become a part of your lifestyle. Those with elevated cholesterol should have aggressive measures of dietary modification and if these measures fail, consider drug therapy.

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