Lipoprotein(a) Changes in Perimenopausal Years

Summary

Several publications, over the last decade, reported the influence of sex hormones on lipoprotein(a) plasma levels. We studied Lp(a) changes in perimenopausal years and the effect of two different schedules of hormone replacement therapy (HRT) on Lp(a) plasma levels. According to menstrual history and FSH plasma levels, 424 women were divided in two groups: 112 were in premenopause and 312 were postmenopausal women with a mean time since last period of 5 years. No difference in Body Mass Index (BMI) was seen between groups, but postmenopausal women were older than premenopausal ones. Lp(a) plasma levels were significantly higher after menopause (p<.01); no significant difference was seen with aging but, at any age considered, premenopausal women have lower Lp(a) plasma levels than the postmenopausal counterpart.

One hundred six out of the 312 postmenopausal women were then enrolled in a open controlled study lasting 6 months. Forty-six were assigned to a transdermal patch regimen (TTS 50) plus medroxyprogesterone acetate (MPA) for 12 days every three months; 32 women were treated with 0.625 mg/day of oral conjugated equine estrogen (CEE) plus MPA for 12 days every three months, and 28 subjects, not receiving treatment, were the control group. Lp(a) plasma levels were tested before starting therapy and after 3 and 6 months of treatment. No difference was seen between groups for age, BMI, years since the last menstrual period, and pretreatment Lp(a) plasma levels. Both HRT regimens significantly lowered Lp(a) plasma levels (- 24%), while, in the control group, no changes were seen, during the study, in Lp(a) concentrations. Data show that Lp(a) plasma levels increase wih age but support the hypothesis that menopause represents the most important risk factor. Results confirm the beneficial effect of HRT and suggest that either oral or transdermal estrogens are equally effective in lowering Lp(a) plasma concentrations.