POSTMENOPAUSAL HORMONE REPLACEMENT THERAPY AND AUTOANTIBODIES AGAINSTOXIDIZED LDL

Objectives: Oxidative modification of low-density lipoprotein (oxLDL) has been suggested to play an important role in the pathogenesis of at herosclerosis, and autoantibodies against oxLDL have recently found to reflect this process. The antioxidant effect and inhibition of LDL ox idation may be one of the cardioprotective mechanisms of postmenopausa l estrogen therapy. Methods: The effects of postmenopausal hormone rep lacement therapy (HRT) on the concentrations of serum lipids and oxLDL autoantibodies were studied in a population-based prospective I-year study with 63 early postmenopausal women (mean age 52.2 +/- 0.4 (S.E.M .) years). The participants were randomized into two treatment groups: HRT-group: Sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate alone or in combination with vitamin D-3, 300 IU/ day + calcium lactate, 500 mg/day (n = 31) and the non-HRT-group: Calc ium lactate, 500 mg/day alone or in combination with vitamin D-3, 300 IU/day (n = 33). The groups were well matched regarding age, body mass index and baseline serum lipid concentrations. Results: The serum con centrations of total cholesterol and LDL-cholesterol decreased in the HRT-group (4.1%, P = 0.05 and 6.4%, P = 0.03, respectively, paired t-t est) but did not change in the non-HRT-group. No changes in the serum concentrations of HDL-cholesterol or triglycerides were observed. Addi tionally, no changes in oxLDL autoantibody concentrations were observe d in either group. Conclusions: Although I-year HRT lowered serum tota l-and LDL-cholesterol levels, it did not influence oxLDL antibody tite rs. On the basis of the present results we cannot question the possibi lity of there being beneficial effects of HRT on the oxidative modific ation of LDL. However, this effect is not reflected in the levels of o xLDL autoantibodies. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.