Abstract
Introduction: The risks of hypertension (HTN) and cardiovascular disease (CVD) rise dramatically in females around the typical age of menopause (TM; menopause age ≥46yr). Early menopause (EM; menopause age <46yr) may substantially increase this risk. Attenuated baroreflex sensitivity (BRS) can be indicative of autonomic dysfunction and has been shown to be a marker of CVD risk. Thus, we aimed to investigate how EM would influence BRS. We hypothesized that females who experienced EM would exhibit attenuated BRS compared to females who experienced TM. Methods: 32 females completed two visits: Visit 1: informed consent, medical and health questionnaires to confirm eligibility, including the Minnesota Leisure Time Physical Activity Questionnaire to assess activity levels. Visit 2: Participants rested in a supine position for 10 min. Non-invasive beat-to-beat blood pressure (BP), heart rate (HR), and muscle sympathetic nerve activity (MSNA) were recorded. Blood was drawn to measure sex steroid levels. Cardiovagal (cBRS) and sympathetic (sBRS) BRS were calculated using the sequence method and Ensemble software, respectively. Both parametric and non-parametric methods were used for the statistical analysis. Results: Results are presented as mean ± SD. Participants in the TM (n=16; age: 63±3yrs, body-mass index (BMI): 25±4kg/m2) and EM (n=16; age: 62±4yrs, BMI: 26±4kg/m2) groups were matched for age and BMI. TM and EM had similar levels of estradiol (TM: 3.9±2; EM: 4.4±4pg/mL) and activity levels (TM: 299±177; EM: 208±147kcal/day), but significantly different menopause ages (TM: 51±3; EM: 43±2yrs; p<0.001). TM and EM had similar resting systolic BP (TM: 129±13; EM: 128±20mmHg), diastolic BP (TM: 79±10; EM: 82±14mmHg), HR (TM: 59±7bpm; EM: 62±9bpm), and MSNA (TM: 51±16; EM: 45±11bursts/100heartbeats), p>0.05 for all. Further, cBRS and sBRS were similar between TM (cBRSup: 9.7±3; cBRSdown: 12.3±7; cBRStotal: 12.3±7ms/mmHg; sBRS: -2.7±1bursts/100Hb/mmHg) and EM (cBRSup: 8.7±4; cBRSdown: 11±5; cBRStotal: 10.4±4ms/mmHg; sBRS: -2±1bursts/100Hb/mmHg; p>0.05 for all). Conclusion: Contrary to our hypothesis, these findings suggest that EM may not influence BRS. These findings indicate that completing menopause early may not disrupt autonomic baroreflex function, suggesting that other mechanisms need to be explored to better understand the increased CVD risk in postmenopausal females who complete menopause prematurely or early. This study was supported by a NIH 1 K01 AG064038-01A1 (MLKR), UMN Grant-in-Aid (MLKR), F32HL160012 (EL), and NIH National Center for Advancing Translational Sciences grant UL1TR002494. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Published Version
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