Lipoprotein(a) and other lipids after oophorectomy and estrogen replacement therapy.

Objective: To assess the effect of surgical menopause and subsequent estrogen replacement therapy (ERT) on lipoprotein(a) [Lp(a)] and common lipids.
Methods: In 24 healthy premenopausal women, lipids (total cholesterol, low-density lipoprotein [LDL] and high-density lipoprotein [HDL] cholesterol, and triglycerides) and gonadotropins (FSH, LH) were measured the day before hysterectomy with bilateral oophorectomy and then after 1, 2, and 3 months. Blood was also drawn after 2, 4, 6, and 15 days to exclude the effect of surgery on Lp(a). In 19 women who volunteered for ERT, the lipid profile was assayed again after 3, 6, and 12 months of treatment.
Results: Lipoprotein(a) levels rose significantly over the 3 months after surgery, from a mean +/- standard deviation (SD) 5.7 +/- 6.1 mg/dL to 10.4 +/- 9.2 mg/dL. Total cholesterol and LDL cholesterol levels increased significantly over the first 2 months; HDL cholesterol decreased significantly during the 3 months of follow-up (by 10, 17, and 20%) (P < .001). Plasma triglycerides did not change after surgery. Three months following ERT, Lp(a) and total cholesterol were significantly decreased (28 and 11%, respectively), as was LDL cholesterol (33%) after 6 months. High-density lipoprotein cholesterol increased by 24% after 6 months of treatment, and triglycerides rose significantly in the year of therapy (37%).
Conclusion: These findings suggest that surgical menopause induces atherogenic changes in the lipid profile in 3 months and that ERT soon reverses them.