Long-term and withdrawal effects of two different oestrogen-progestogen combinations on lipid and lipoprotein profiles in post-menopausal women.

Serum lipids and lipoproteins were studied in 86 healthy post-menopausal women at 3-monthly intervals throughout 2 yr of treatment with cyclic oestradiol valerate plus cyproterone acetate (E2V + CPA), continuous 17 beta-oestradiol plus norethisterone acetate (E2 + NETA), or placebo. Withdrawal effects were also investigated. Serum oestrogen levels were similar following the 2 hormone regimens. Serum total and low-density-lipoprotein (LDL) cholesterol were significantly reduced by 5-8% during cyclic E2V + CPA therapy and by 15-20% during continuous E2 + NETA treatment. The concentrations remained significantly reduced throughout the 2 yr of treatment. Virtually no changes were observed in the placebo group. High-density-lipoprotein (HDL) cholesterol concentrations were significantly reduced in relation to pretreatment values during the first year of continuous E2 + NETA therapy, but were not significantly different from the levels in the cyclic E2V + CPA or the placebo groups. Serum triglyceride levels remained almost constant in all the groups. Withdrawal of hormone therapy resulted in steep increases in total and LDL-cholesterol, the levels returning to pretreatment values. A similar increase in HDL-cholesterol was observed in the E2 + NETA group, following withdrawal. Vaginal bleeding episodes were experienced by all the women receiving the E2V + CPA regimen and they occurred regularly in 63% of the women. Fifty-two (52) percent of the women receiving E2 + NETA did not bleed at all. The results of the present study suggest that the continuous addition of NETA may enhance the oestrogen-induced changes in total and LDL-cholesterol, whereas only minor changes in the oestrogen-induced effects on these variables are produced by the cyclic addition of CPA. However, in the case of HDL-cholesterol, the antagonistic effect of CPA seems to be moderate in comparison with that of NETA.