Abstract
This randomized double-blinded, placebo-controlled clinical trial evaluated the progression of intima-media thickness of common carotid artery (cIMT) and the effect of phytoestrogen therapy on atherosclerosis development in early and late postmenopausal women. The 2-year cIMT progression was evaluated in 315 early postmenopausal women aged 40-55 years and in 231 late postmenopausal women aged 60-69 years free of cardiovascular disease. B-mode ultrasound was done at baseline and after 12 and 24 months of follow-up. The study revealed no significant changes in the rate of cIMT progression in 315 early postmenopausal women. By contrast, a statistically significant difference in the rate of atherosclerosis development was observed in late postmenopausal women treated with phytoestrogens compared to placebo (p = 0.008). The rate of cIMT progression in the placebo group was 0.019 mm/year led to a significant increase of cIMT during the observation period (p = 0.012), while the rate of cIMT progression in phytoestrogen late postmenopausal recipients was 0.011 mm/year, and total change did not reach statistical significance during the follow-up period (p = 0.101). These results suggest that late postmenopausal women can be a suitable cohort for trials assessing the anti-atherosclerosis effects of phytoestrogen preparations. In particular, the beneficial effect of phytoestrogens on cIMT progression was demonstrated in late postmenopausal women.