Coronary artery disease incidence

Oomen, C.M., Ocke, M.C., and Feskens, E.J.M. 2001. a-Linolenic acid intake is not beneficially associated with 10-y risk of coronary artery disease incidence The Zutphen elderly study. Am. J. Clin. Nutr. 74, 457 463. 

We hear a lot these days about the relationships between saturated fats, cholesterol, and heart disease. What are the facts It s well established that a diet rich in saturated animal fats often leads to an increase in blood serum cholesterol, particularly in sedentary, overweight people. Conversely, a diet-lower in saturated fats and higher in polyunsaturated fats leads to a lower serum cholesterol level. Studies have shown that a serum cholesterol level greater than 240 mg/dL (a desirable value is <200 mg/dL) is correlated with an increased incidence of coronary artery disease, in which cholesterol deposits build up on the inner walls of coronary arteries, blocking the flow of blood to the heart muscles. 

Low levels of vitamin E have been associated with increased incidence of coronary artery disease. Observational studies have therefore suggested that supplemental a-tocopherol might have value in the treatment of cardiovascular disease. Clinical studies demonstrated contradicting results regarding the benefits of vitamin E in the prevention of cardiovascular disease. Four... 

An increase in serum lipids is believed to contribute to or cause atherosclerosis, a disease characterized by deposits of fatty plaques on the inner walls of arteries. These deposits result in a narrowing of the lumen (inside diameter) of the artery and a decrease in blood supply to the area served by the artery. When these fatty deposits occur in the coronary arteries, the patient experiences coronary artery disease. Lowering blood cholesterol levels can arrest or reverse atherosclerosis in the vessels and can significantly decrease the incidence of heart disease. 

These studies demonstrate that optimal doses of statins reduce the incidence of clinical events in patients with established coronary artery disease, in patients with elevated plasma LDL levels but without existing coronary artery disease, in individuals with normal plasma LDL levels without existing coronary artery disease, and in diabetics, a patient population at high risk of cardiovascular disease. ... 

The statins have been demonstrated to reduce the incidence of clinical events (e.g., heart attacks) in patients known to have coronary artery disease as well as in patients with both elevated and normal levels of cholesterol without coronary artery disease. 

The clinical problems that arise in the menopause are hot flushes, sweating, depression, decreased libido, increased risk of cardiovascular disease and osteoporosis. The latter results in increased incidence of hip, radial and vertebral fractures. Oestrogen is one factor controlling synthesis of active vitamin D and osteoporosis is in part due to a deficiency of vitamin D. Not surprisingly, to reduce these problems, administration of oestrogen is recommended (known as hormone replacement therapy or HRT). HRT reduces some of the risk factors for coronary artery disease since it reduces blood pressure and decreases the blood level of LDL-cholesterol and increases that of HDL-cholesterol. However, there is considerable debate about whether HRT increases the risk of breast or endometrial cancer. 

In a totally different field, studies were being carried out on children who had a deficiency of methionine synthase and an impaired ability to convert homocysteine to methionine, so that they had increased blood levels of homocysteine. It was noted that these children had an increased incidence of thrombosis in cerebral and coronary arteries. This led to a study which eventually showed that an increased level of homocysteine was a risk factor for coronary artery disease in adults. Since methionine synthase requires the vitamins, folic acid and B12, for its catalytic activity, it has been suggested that an increased intake of these vitamins could encourage the conversion of homocysteine to methionine and hence decrease the plasma level of homocysteine. This is particularly the case for the elderly who are undernourished (see Chapter 15 for a discussion of nutrition in the elderly). 

The role of the antioxidant properties of vitamins C, E, and p-carotene in the prevention of cardiovascular disease has been the focus of several recent studies. Antioxidants reduce the oxidation of low-density lipoproteins, which may play a role in the prevention of atherosclerosis. However, an inverse relationship between the intake or plasma levels of these vitamins and the incidence of coronary heart disease has been found in only a few epidemiological studies. One study showed that antioxidants lowered the level of high-density lipoprotein 2 and interfered with the effects of lipid-altering therapies given at the same time. While many groups recommend a varied diet rich in fruits and vegetables for the prevention of coronary artery disease, empirical data do not exist to recommend antioxidant supplementation for the prevention of coronary disease. 

Although elevated levels of cholesterol and LDL in human plasma are linked to an increased incidence of cardiovascular disease, recent data have shown that an increase in concentration of HDL in plasma is correlated with a lowered risk of coronary artery disease. Why does an elevated HDL level in plasma appear to protect against cardiovascular disease, whereas an elevated LDL level seems to cause this disease The answer to this question is not known. An explanation currently favored is that HDL functions in the removal of cholesterol from nonhepatic tissues and the return of cholesterol to the liver, where it is metabolized and secreted. The net effect would be a decrease in the amount of plasma cholesterol available for deposit in arteries (see... 

The causes of human copper deficiency include (1) low intake - malnutrition, total parenteral nutrition (TPN) (2) high loss - cystic fibrosis, nephrotic syndromes and (3) genetic factors — Menkes disease. Copper deficiency may also be associated with chronic malabsorption, a situation which is made much worse in cases of gastric and bowel resection. Several special diets, including powdered milk, liquid protein and standard hospital diets are a means of inducing copper deficiency. The amount of copper in US food has decreased steadily since 1942, and may be related to the rising incidence of coronary artery disease. A copper deficiency may also occur as the result of the use of chelators for other purposes for example, diethyl dithiocarbamate is an in vivo metabolite of ANTABUSE (disulfiram). 

The risk of embolism associated with mechanical heart valves is 2 to 6% per patient per year despite anticoagulation and is highest with valves in the mitral position. Warfarin therapy (INR 2.5 to 3.5) is recommended in these patients. The addition of enteric-coated aspirin (100 mg/d) to warfarin (INR 3.0 to 4.5) in high-risk patients (preoperative atrial fibrillation, coronary artery disease, history of thromboembolism) with mechanical valves decreases the incidence of systemic embolism and death from vascular causes (1.9 vs. 8.5% per year), but increases the risk of bleeding. 

Diabetes is extremely prevalent within the United States, with more than 16 million confirmed cases and an additional 20 million cases of glucose intolerance, As the incidence of diabetes in this country is thought to be on the rise (I), coronary artery disease (CAD) in this group, which is the principal cause of death in this population, is expected to rise concomitantly (2), Clearly reflecting these trends, in over a 20-year period, the mortality rate in the United States from diabetes has risen more than 30% (3). 

People with pre-existing coronary artery disease may have an increased incidence of attacks of angina (146). In individuals who are vulnerable to schizophrenia, cannabis can precipitate psychoses or aggravate schizophrenia. The control of epilepsy may be impaired. Users undergoing anesthesia may react unexpectedly and may have enhanced nervous system depression. Because of impairment of judgement and psychomotor performance, users should not drive or operate machinery for at least 24 hours after administration. 

Further support for using blood pressure as a surrogate endpoint is provided by the concordance of evidence from a number of clinical trials in which blood pressure lowering with low-dose diuretics and P-blockers was shown to reduce the incidence of stroke/ coronary artery disease/ and congestive heart failure in hypertensive patients (19). Of particular interest is a meta-analysis that was conducted to compare the extent of blood pressure reduction achieved in different clinical trials with the maximum benefit that was anticipated on epidemiolgic grounds (Table 17.3) (20). The decrease in stroke incidence anticipated for a 5- to 6-mm Hg average reduction in diastolic blood pressure was fully realized with only 2 to 3 years of antihypertensive therapy. 

Besides its hepatotoxic effects, beta-carotene supplementation can also cause cardiovascular complications in smokers and potentiate carcinogenicity. The Alpha-Tocopherol, Beta-Carotene and Cancer Prevention Study (ATBC) (72) and CARET (99) showed that supplementation of beta-carotene in smokers increased the incidence of death from coronary artery disease. Recent results suggest that beta-carotene participates as a prooxidant in the oxidative degradation of LDL, and that raised LDL concentrations may cancel the protective effect of alpha-tocopherol (102). 

One case of an acute lateral wall myocardial infarction (MI) was reported in a woman after daily ingestion of Edita s Skinny Pill (containing 300 mg bitter orange plus caffeine and guarana) for 1 year (44). The 55-year-old Caucasian woman developed chest discomfort after eating Chinese food. After workup at the hospital, the woman was diagnosed with acute lateral-wall MI and smoking addiction. Her ejection fraction was 0.45. Prior to this incident, she had no known coronary artery disease, hypertension, or hyperlipidemia. 

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