Effect of age at menopause on blood pressure in postmenopausal women.

Background: A major mechanism of hypertension in many postmenopausal women is deficiency of female gonadal steroids. A long postmenopausal period may thus represent one factor that influences the prevalence of hypertension because of long periods of estrogen loss. Methods: When we conducted a medical survey in northwestern China, we also asked 150 postmenopausal female subjects to provide age at menopause in a questionnaire. Age at menopause ranged from 37 to 57 years for all subjects. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) in all subjects were obtained from 24-h ambulatory blood-pressure monitoring. Results: An inverse correlation was identified between age at menopause and SBP and DBP, and a positive correlation was found between postmenopausal period and either SBP or DBP. Blood pressure, age at menopause, and postmenopausal period were not significantly related to body mass index, plasma renin activity, glomerular filtration rate, or urinary excretion values of sodium and potassium. Conclusions: Our results clearly demonstrated that higher blood-pressure levels in postmenopausal women depend on age at menopause and postmenopausal period, but not subjects' age, suggesting that a longer absence of female gonadal steroids represents a major factor contributing to increased blood pressure in elderly women.