Effect of oral estradiol on Lp(a) and other lipoproteins in postmenopausal women. A randomized, double-blind, placebo-controlled, crossover study.
BACKGROUND
Lp(a) lipoprotein level is an independent risk factor for premature coronary artery disease and cerebrovascular accident. Concentrations of this lipoprotein tend to increase after menopause.


OBJECTIVE
To determine whether oral estrogen was effective in lowering concentrations of Lp(a) lipoprotein in postmenopausal women.


METHODS
A double-blind, placebo-controlled, cross-over study was conducted during a 12-month period in 100 postmenopausal women who had undergone hysterectomy. They were randomized into two groups: group 1 received oral estradiol, 2 mg/d, for the first 6 months and placebo for the second, and group 2 received these treatments in the reverse order. After completion of the crossover study, the effect of prolonged administration of oral estradiol was examined by placing all patients on active treatment and repeating the lipoprotein measurements approximately 12 months later.


RESULTS
No significant differences were noted between the two groups at the commencement of the study (median concentration of Lp[a] lipoprotein, 10.78 mg/dL [range, 2.2 to 108.5 mg/dL] in group 1 and 12.74 mg/dL [range, 0.8 to 98.1 mg/dL] in group 2). Crossover analysis showed a 9.62% reduction in values of Lp(a) lipoprotein with estradiol treatment compared with placebo during 12 months of treatment (P < .001). With prolonged treatment, the median concentration of Lp(a) lipoprotein for those in group 1 decreased from 8.12 mg/dL (range, 1.05 to 57.4 mg/dL) to 5.77 mg/dL (range, 0.84 to 75.39 mg/dL) (P < .001). In group 2, the median concentration decreased from 8.19 mg/dL (range, 2.52 to 99.82 mg/dL) to 7.07 mg/dL (range, 0.70 to 48.79 mg/dL), but this difference was not significant (P = .63).


CONCLUSIONS
The results of this study confirm the beneficial effect of oral estradiol on the basic lipoprotein pattern and demonstrate that this treatment is effective in reducing concentrations of Lp(a) lipoprotein in postmenopausal women.
Haines
C
C
Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, New Territories.
Chung
T
T
Chang
A
A
Masarei
J
J
Tomlinson
B
B
Wong
E
E
D000284:Administration, Oral; D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004338:Drug Combinations; D004958:Estradiol / Q000494:pharmacology*; D004964:Estriol / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood* / Q000187:drug effects*; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood* / Q000187:drug effects*
D004338:Drug Combinations; D017270:Lipoprotein(a); C044003:estradiol, estriol drug combination; D004958:Estradiol; D004964:Estriol