Hormone replacement therapy and longitudinal changes in blood pressure in postmenopausal women

Background: The incidence of hypertension in postmenopausal women exceeds t hat in age-matched men. Longitudinal studies relating hormone replacement t herapy (HRT) to blood pressure changes are sparse. Objective: To investigate the association between HRT and longitudinal chan ges In blood pressure In postmenopausal women. Design: Longitudinal observational study. Setting: Community-dwelling volunteers. Patients: 226 healthy, normotensive postmenopausal women from the Baltimore Longitudinal Study of Aging with a mean (+/- SD) age of 64 +/- 10 years we re followed for 5.7 +/- 5.3 years. Seventy-seven women used both estrogen a nd progestin, and 149 used neither. Measurements: Lifestyle variables, blood pressure, and traditional cardiova scular risk factors were measured at baseline and approximately every 2 yea rs thereafter. Results: Systolic blood pressure at baseline was similar in HRT users and n onusers (133.9 +/- 16.0 mm Hg vs. 132.4 +/- 14.8 mm Hg). Over time, average systolic blood pressure increased less in HRT users than nonusers, indepen dent of other cardiovascular risk factors, physical activity, and alcohol u se. For example, HRT users who were 55 years of age at their first Baltimor e Longitudinal Study of Aging visit experienced a 7.6-mm Hg average increas e in systolic blood pressure over 10 years; in contrast, the average increa se in nonusers was 18.7 mm Hg. The lesser increase in systolic blood pressu re in HRT users was more evident at older age. Diastolic blood pressure, wh ich did not change statistically over time in either group, was not associa ted with HRT. Conclusion: Postmenopausal women taking HRT have a smaller increase in syst olic blood pressure over time than those not taking HRT. This difference is intensified at older ages.