The data were used to extend Dr. Gofman's initial study from 10 to 30 years of follow-up. Survival analysis was used to assess the independent contributions of specific lipoprotein subclasses to coronary disease while controlling for other risk factors. Other issues examined were whether HDL2 and HDL3 showed different relationships to coronary disease, whether the relationships of lipoprotein subfractions to coronary disease were independent of other established risk factors, and whether measurements of lipoprotein subfraction concentrations offered significant improvement over total cholesterol in predicting coronary disease risk.