Estradiol-17β reduces blood pressure and restores the normal amplitude of the circadian blood pressure rhythm in postmenopausal hypertension

After menopause, both systolic (SBP) and diastolic (DBP) blood pressure (BP) become higher in women than in men of the same age, suggesting that estrogen deficiency may influence the age-related increase in BP. We studied 30 postmenopausal women (mean age, 55 +/- 5.7 years; time from menopause, 2-5 years) affected by mild hypertension with no target-organ complications by means of 24-h BP monitoring. None of the group were undergoing estrogen replacement therapy or taking antihypertensive drugs. According to a randomized, double-blind protocol, subjects received patches of transdermal estradiol-17beta (E2) or a matched placebo, with crossover after a 7-day washout period. In 12 patients the 24-h peak-to-trough variation in SBP and DBP amounted to less than 10% (nondippers). Administration of E2 significantly decreased 24-h SBP and DBP in the whole cohort (P < .05). Furthermore, E2 restored the expected reduction in BP during nighttime in the nondipper subgroup. It is well known that estrogen replacement therapy protects against the development of both cardiovascular diseases and stroke. Our data suggest that this activity could be attributed, at least in part, to the activity of E2 in preserving physiologic circadian fluctuation of BP.