Psychosocial Factors and Aging: Resting/Reflexive Cardiovascular Control

描述(由申请人提供)：几十年来，我们已经知道较低的心率(HR)与降低发病率和死亡率有关。但人力资源并不稳定--它天生就是“嘈杂的”，在平均值上下波动。从20世纪80年代开始，这些振荡的临床和生理意义，现在被称为心率变异性(HRV)，已经被认识到。心率变异性可预测心肌梗塞或心力衰竭诊断后的不良结果、冠心病患者动脉粥样硬化的进展，以及健康社区样本中冠心病的发展。因此，测量心率中的“噪声”现在被认为是心血管健康的一个有价值的指标。今天，血压(BP)与40年前的HR处于类似的位置。虽然平均血压(BP)的临床意义已经被接受了几十年，但受试者内部的BP在多个时间尺度上有很大的差异。曾经被认为是噪音的BP变异性(BPV)现在也被认为包含有价值的信息。重复测量数周甚至数年，临床到临床血压的标准差(SD)预测12-14年后高血压的发展和死亡率。在24小时尺度上，每30分钟测量一次的血压标准差与8.5年后的心血管死亡率和更大的靶器官损害有关。在更短的时间范围内，BP在节拍的基础上有所不同。该领域的共识是，BPV的最终预后价值可能需要分析这些心跳至心跳的BP振荡。然而，由于测量这些更快速的振荡在技术上要求很高，BPV与临床或与健康相关的心理社会变量之间的关联尚未建立。技术的进步使BPV变得越来越普遍，探索其与心血管健康以及相关的社会人口学和心理社会性心血管风险因素的关系有可能产生重要的临床和生理见解。测量心率间期BP和RR间期也可以计算压力反射敏感性(BRS)，即RR间期的反射性变化与BP变化的关系。虽然BPV可能代表紧张性自主神经指数，但BRS是自主神经反射的指数，可预测MI和心力衰竭后的不良后果。然而，据我们所知，关于BPV和BRS的社区研究还不存在。我们建议分析已经从参与者那里收集的节拍血压数据，但没有从参与者那里进行分析，以应对来自美国中年数据收集(MIDUS II)研究的第二波数据收集的心理和立位挑战。我们在R21中的目标是检查静息和反应性BPV和BRS之间的关系以及年龄范围内的心理社会和生物标记物数据，并进行探索性前瞻性分析，以测试更大的BPV和更低的BRS是否与更高的死亡率相关。

DESCRIPTION (provided by applicant): For decades, we have known that lower heart rate (HR) is associated with reduced morbidity and mortality. But HR is not stable - it is inherently "noisy," oscillating around the mean. Beginning in the 1980s, the clinical and physiological significance of these oscillations, now known as Heart Rate Variability (HRV), has been recognized. HRV predicts adverse outcomes following myocardial infarction or diagnosis of heart failure, progression of atherosclerosis in CAD patients, and the development of CAD in healthy community samples. Thus, measurement "noise" in HR is now recognized as a valuable index of cardiovascular health. Today, blood pressure (BP) is in a similar position as HR was 40 years ago. While the clinical significance of mean blood pressure (BP) has been accepted for decades, within-subject BP varies considerably across multiple time scales. Once dismissed as noise, BP variability (BPV) now also is thought to contain valuable information. Measured repeatedly over weeks or even years, the standard deviation (SD) of clinic-to-clinic BP predicted the development of hypertension and mortality after 12-14 years follow-up. On a 24-hour scale, the SD of BP measured every 30 min was associated with cardiovascular mortality after 8.5 years follow-up and with greater target organ damage. At a still shorter time scale, BP varies on a beat-to-beat basis. Consensus in the field is that the ultimate prognostic value of BPV may require analysis of these beat-to-beat BP oscillations. However, because measurement of these more rapid oscillations has been technically demanding, associations of beat-to-beat BPV with clinical or with psychosocial variables linked to health have not been established. Technological advances have made beat-to-beat BPV increasingly available and exploration of its relationship to cardiovascular health and contextual sociodemographic and psychosocial cardiovascular risk factors has the potential to yield important clinical and physiological insights. Measuring beat-to-beat BP along with RR intervals also allows for computation of baroreflex sensitivity (BRS), the relationship of reflexive changes in RR interval to changes in BP. While BPV may represent a tonic autonomic index, BRS is an index of autonomic reflexes that predicts adverse outcomes after MI and in heart failure. However, to our knowledge, community studies of BPV and BRS do not exist. We propose to analyze the beat-to-beat BP data already collected but not analyzed from participants at rest and in response to psychological and orthostatic challenge from the wave 2 of data collection in the Midlife in the US (MIDUS II) study. Our aims in this R21 are to examine relationships between resting and reactive BPV and BRS and psychosocial and biomarker data across the age spectrum and in an exploratory prospective analysis, to test whether greater BPV and lower BRS are associated with greater mortality.