Effect of Hormone Therapy on Lipoprotein Subfractions in Early and Late Postmenopausal Women.

CONTEXT: The Early vs Late Intervention Trial with Estradiol (ELITE) showed that hormone therapy (HT) reduced atherosclerosis progression among early but not late postmenopausal women (PMW).

OBJECTIVE: Determined by time-since-menopause (1) HT effects on lipids and lipoprotein particle subfractions (LPs), (2) associations of estradiol (E2) level with lipids and LPs, (3) associations of lipids and LPs with atherosclerosis progression.

DESIGN: Randomized controlled trial stratified by time-since-menopause.

SETTING: Academic institution.

PARTICIPANTS: Healthy postmenopausal women.

INTERVENTION: Oral E2 with/without sequential vaginal progesterone.

MAIN OUTCOME MEASURES: Standard lipids and 21 LPs quantitated by ion mobility every 6 months.

RESULTS: Among 562 PMW (240 early, 322 late), HT significantly increased total triglycerides (TG), high-density lipoprotein (HDL) cholesterol, small low-density lipoproteins (LDL), large HDL, and TG/C ratio in LDL and HDL and decreased LDL-cholesterol, total very low density lipoproteins (VLDL), small VLDL, intermediate-density lipoproteins, large LDL, and LDL peak diameter. HT showed no lipid or LP differences between time-since-menopause. Associations of E2 level with lipids and LPs explained the HT effects. Despite the nonsignificant P interaction by time-since-menopause, we observed that very small LDL and total HDL LPs were associated with atherosclerosis progression in late PMW.

CONCLUSION: HT effects on standard lipids and LPs are consistent with the literature. HT has similar effect on lipids and LPs in early and late PMW. Novel findings include discordant effects of HT on TG and VLDL particles, which can be explained by increased catabolism of atherogenic remnants of TG-rich lipoproteins. Our findings extend the well-known HT effects on standard lipids and LPs that may contribute to the beneficial effects on atherosclerosis progression in PMW.