ESTROGEN REPLACEMENT THERAPY AND PROGRESSION OF INTIMAL-MEDIAL THICKNESS IN THE CAROTID ARTERIES OF POSTMENOPAUSAL WOMEN

The effect of estrogen replacement therapy (ERT) on 3-year changes in carotid intimal-medial thickness (IMT) was explored using serial B-mod e ultrasound measurements collected during 1989-1993 as part of the As ymptomatic Carotid Atherosclerotic Progression Study (ACAPS). Eligibil ity included increased IMT and elevated low density lipoprotein choles terol. Of the 186 postmenopausal ACAPS women randomly assigned to rece ive either placebo or lovastatin, 34% reported use of ERT. Users tende d to be younger than nonusers by an average of 3 years, to have more f avorable high and low density lipoprotein cholesterol levels, and to b e more likely to have had hysterectomies. Baseline blood pressure, bod y mass index, and cross-sectional IMT were similar among ERT users and nonusers. In the placebo group, IMT tended to progress among ERT nonu sers but to regress among ERT users: Mean covariate-adjusted progressi on rates were 0.015 +/- 0.007 mm/year versus -0.012 +/- 0.012 mm/year, respectively (p = 0.05). This difference appeared to be independent o f lipoprotein concentrations. Lovastatin was associated with an approx imately 25% lowering of low density lipoprotein cholesterol among both ERT users and nonusers and had a marked impact on IMT progression (p = 0.004) in these women. ERT appeared to have little additional effect on IMT in women assigned to lovastatin. ERT may reduce or halt the pr ogression of early atherosclerosis in women not receiving active lipid -lowering medication.