Hormone replacement therapy and plasma homocysteine levels

OBJECTIVE: To compare the effects of 4 and 12 weeks of combined estradiol-progestogen replacement with unopposed estradiol therapy on fasting plasma total homocysteine concentrations in healthy postmenopausal women. METHODS: In this prospective, 12-week study in healthy postmenopausal women, we randomly assigned 59 women to sequentially combined daily 2 mg estradiol (E2) plus either trimegestone 0.5 mg daily or dydrogesterone 10 mg daily (n = 28), or to unopposed daily 2 mg estradiol (n = 16), or to placebo (n = 15). RESULTS: Fasting plasma total homocysteine concentrations decreased by 9.4% in the combined estradiol-progestogen group and by 5.1% in the estradiol-only group, and they increased by 2.4% in the placebo group (analysis of covariance: combined hormone replacement therapy compared with placebo (P = .02); combined therapy compared with estradiol (P = .23); and estradiol compared with placebo (P = .26). Reductions were detectable after 4 weeks of combined estradiol-progestogen treatment. The data suggest an additional progestogen-related reduction in homocysteine levels of 0.7 micromol/L and 0.4 micromol/L after 4 and 12 weeks, respectively. Women with a baseline homocysteine concentration in the highest quartile had significantly greater reductions in homocysteine compared with women with an initial homocysteine value in the lowest quartile. CONCLUSION: Fasting total homocysteine concentrations were significantly reduced by combined estradiol-progestogen replacement. Women with high homocysteine levels at baseline benefit the most. The progestogens used in this study did not have an unfavorable effect on homocysteine metabolism.