Abstract-We compared serum lipid and apolipoprotein predictors of atherosclerosis in cases from the multicenter study, Pathobiological Determinants of Atherosclerosis in Youth (PDAY). The lipid measures included HDL cholesterol (HDL-C) and non-HDL-C, and the apolipoprotein measures included concentrations of apoA1, apoB, and Lp(a), and sizes of the apo(a) proteins. We tested whether the apolipoprotein measures predicted atherosclerotic lesions as well as the more traditional lipid measures. We estimated extent of lesions as fatty streaks or raised lesions (fibrous plaques, complicated or calcified lesions) in 3 sites: thoracic aorta, abdominal aorta, and right coronary artery. Neither apoA1 nor apoB measures were as strongly or consistently correlated with extent of lesions as the corresponding lipid measure (HDL-C and non-HDL-C, respectively). Beyond the basic model that included sex, age, race, smoking status, hypertension, and the lipid measures, apoA1 and apoB added only an average 1.3% increased explanatory ability to the model, whereas HDL-C plus non-HDL-C added an average 2.5%. The results suggest that the traditional lipid measures are more useful than apolipoprotein measures for detecting young persons at high risk of precocious atherosclerosis.Because of large racial differences, the two Lp Key Words:arly studies of the relationship of plasma lipids to atherosclerosis and coronary heart disease (CHD) emphasized the cholesterol content of plasma, although it was known that cholesterol and other lipids were transported as lipid-protein complexes. Ultracentrifugation separated these lipoproteins into classes by their hydrated density 1 ; electrophoresis, by electrical charge 2 ; and chemical methods, by selective precipitation. 3 After the specific protein components were isolated and characterized, methods were developed to measure the proteins (apolipoproteins) directly by immunochemical methods, 4 including a rapid and reliable electroimmunoassay method. 5 Alaupovic 6 first suggested that measuring the apolipoproteins might be more useful in predicting risk of CHD than the lipid components or intact lipoprotein particles.During the 1970s and 1980s, a number of studies of the ability of plasma or serum apolipoprotein concentrations to predict risk of atherosclerotic disease produced conflicting and inconclusive results (reviewed by Sniderman and Silberberg 7 and Vega and Grundy 8 ). Some of these studies examined the association of apolipoprotein levels with atherosclerotic lesions measured by angiography or ultrasound in living persons, but none examined the relationship with atherosclerosis measured directly in the arteries of autopsied persons.A multicenter cooperative study of atherosclerosis in young persons, Pathobiological Determinants of Atherosclerosis in Youth (PDAY), 9 has provided an opportunity to compare the usefulness of serum concentrations of apoB and apoA1 with the usefulness of lipoprotein cholesterol concentrations to predict atherosclerotic lesions in 15-to 34-year-old men and women...
