REDUCTION OF SERUM-CHOLESTEROL LEVELS AND REGRESSION OF ATHEROSCLEROSIS

National mortality statistics have been used to demonstrate an 'epidemic' rise in the incidence of coronary heart disease (CHD) in western industrialized countries since the turn of the century. The alleged epidemic continues but with a declining incidence in several countries (including Australia and New Zealand) since 1968, leading to claims that CHD can be prevented. 1 since conventional wisdom holds that a high cholesterol/animal fat diet is responsible for elevated serum cholesterol and, in turn, the development of atherosclerosis in man and experimental animals, many animal regression studies have been undertaken. Regression of the lipid content and reduced narrowing in traumatized arteries of cholesterol-fed animals 2,3 strengthened the belief that prevention of CHD was possible in man. Recommendations have been made for dietary changes in whole populations and for governmental restraint of those who may obstruct such prevention. 4 In the past 20 years, many clinical trials have been undertaken to determine whether reduction in serum cholesterol lessened the incidence of CHD and, by extrapolation, atherosclerosis severity. These trials have evoked criticisms, while others consider they have proven the lipid hypothesis beyond reasonable doubt. 5 This review appraises the methodology and results of several recent major trials.