Interrelationships among subgroups of serum lipoproteins in normal human subjects.

Analytic ultracentrifugation of serum lipoproteins from 80 men and 54 women aged 27--66 was used to determine if specific segments of the high density (HDL), low density (LDL) and very low density (VLDL) lipoprotein schlieren curves could be defined so as to reveal significant correlations among them. Differences in correlations resulted in division of LDL into three subgroups based on flotation rate S(0)(f) 0--7, 7--12, and 12--20) and division of HDL into two subgroups F(0)(1.20) 0--1.5 and s--9). HDL of F(0)(1.20) 2--9 (designated HDL 2--9) correlated negatively with LDL of S(0)(f) 0--7 (LDL 0--7) for all groups, positively with LDL of S(0)(f) 7--12 except in women aged 27--46, and negatively with VLDL except in men aged 47--66. HDL of F1.20(0) 0--1.5 (HDL0-1.5) correlated positively with LDL 0-7 except in men aged 27--46 and with VLDL in all but older men. Some correlations were reduced to non-significant levels by controlling for LDL (0-7) or VLDL. Correlations of HDL and LDL flotation subgroups yielded no significant net correlation between total HDL and LDL. Total HDL was directly correlated with HDL (2-9) (r greater than 0.97) but not with HDL0-1.5. The foregoing suggests that decreased HDL represents reduced HDL2-9 and may be accompanied by increased LDL0-7 and VLDL. LDL0-7 may represent and "atherogenic" LDL subclass in part responsible for increased coronary risk associated with low HDL.