High-density lipoprotein (HDL) particles exhibit considerable heterogeneity, specifically in apolipoprotein (apo) composition. Thus, apo A-I, the major protein of HDL, is present in two types of particles: one species contains both apo A-I and apo A-II (Lp A-I/A-II) while in the other (Lp A-I), apo A-II is absent. We used the hypothesis that octogenarians, who survived periods in life when the incidence of coronary heart disease (CHD) is very high, have several protective factors. We compared HDL-cholesterol (HDL-C), HDL2-cholesterol (HDL2-C), HDL3-cholesterol (HDL3-C), apo A-I, and apo A-II in octogenarians and younger control subjects smoking less than 10 cigarettes/d and not taking drugs known to affect lipid metabolism. Using a new procedure, we also compared the levels of Lp A-I and Lp A-I/A-II. The cholesterol content of total HDL was similar in octogenarian and control (38 +/- 8 years) men while HDL2-C was higher and HDL3-C, apo A-I, and A-II were lower in octogenarian than in control men. In women, the level of HDL-C and apo A-I was similar in premenopausal and octogenarian subjects but higher in postmenopausal women than in octogenarians, while HDL2-C and apo A-II were similar in the three groups. In contrast, HDL3-C was higher in the two groups of control women (premenopausal and postmenopausal) than in octogenarians. However, Lp A-I was significantly elevated in octogenarian men and women (men: 61 +/- 14 mg/dL; women: 70 +/- 14 mg/dL) by comparison with younger control subjects (men: 48 +/- 12 mg/dL; premenopausal women: 53 +/- 11 mg/dL; postmenopausal women: 63 +/- 19 mg/dL).(ABSTRACT TRUNCATED AT 250 WORDS)