Mechanisms of Meditation in Hypertension in Blacks

描述(申请人提供)：与美国白人相比，非裔美国人的高血压更普遍，发病年龄更早，倾向于更严重，更频繁地未被诊断和治疗。先前的研究表明，在这一少数民族人群中，高水平的心理社会和环境压力导致了高血压的不成比例比例。已提出的这种效应的机制包括交感神经系统过度激活和心血管反应性。该中心团队此前在患有高血压的非裔美国人人群中进行的随机对照试验表明，与健康教育控制(HE)干预相比，在短期和长期的随访期内，先验冥想(TM)计划的压力减轻干预与血压水平的降低有关。这一效应可能有助于降低在非洲裔美国人使用冥想的临床试验中观察到的心血管发病率和死亡率。然而，关于这种临床效应的生理机制的数据很少。因此，本研究的总体目标是在这一高危少数民族人群中探讨冥想对心血管和自主神经系统高血压的急性和慢性影响机制。这将是一项随机对照机械试验，对象为152名40岁及以上的高血压非裔美国成年人，他们将被分配到TM计划或HE对照组，为期三个月。实验方案将在实验室测试临床血压、动态血压以及对应激的慢性和急性生理反应。急性实验室应激源包括心算、冷加压和运动跑步机。具体地说，我们将评估心血管和血浆儿茶酚胺对实验室应激源的反应性；血液动力学反应，包括心率、血压、每搏量、心输出量和总外周阻力；动脉顺应性，以及使用心率变异性的心脏自主神经系统张力。实验室血压模式将与自然环境中的动态血压监测进行比较。将通过回归模型对干预影响血压的可能中介因素(即心理社会因素、行为因素、自主神经张力、心血管反应性和血流动力学因素)进行标准中介变量分析。这项研究的结果将提供关于心血管、神经内分泌、自主神经和行为机制的迫切需要的数据，通过这些机制，减压干预可以降低这一非裔美国人的血压，从而预防和治疗高血压。 该应用程序具有几个优点，包括调查团队的专业知识、调查员先前工作的扩展、理解潜在的生物、行为和心理社会因素的“翻译”方法、理论上强有力的措施的使用、随机对照研究设计以及研究成功完成的高可能性。然而，有几个次要的研究设计问题似乎都是可以补救的。总体来说，人们对这一应用程序的热情仍然很高。

DESCRIPTION (provided by applicant): Hypertension is more prevalent, starts at an earlier age, tends to be more severe and more frequently remains undiagnosed and untreated in African Americans compared to white Americans. Previous studies indicate that high levels of psychosocial and environmental stress contribute to these disproportionate rates of hypertension in this minority population. Proposed mechanisms for this effect include excess sympathetic nervous system activation and cardiovascular reactivity. Previous randomized controlled trials in African American populations with high blood pressure conducted by the Center team have demonstrated that stress reduction intervention with the Transcendental Meditation (TM) program is associated with reduced blood pressure levels compared to health education control (HE) intervention over short and long-term follow-up periods. This effect may contribute to reduced cardiovascular morbidity and mortality rates observed in clinical trials with African Americans using meditation. However, there is a paucity of data on the physiological mechanisms for this clinical effect. Therefore, the overall objective of this study is to investigate acute and chronic effects of meditation on cardiovascular and autonomic nervous system mechanisms of high blood pressure in this high-risk minority population. This will be a randomized controlled mechanistic trial of 152 hypertensive African American adults 40 years and older who will be allocated to either the TM program or a HE control group for three months. The experimental protocol will test for clinic BP, ambulatory BP, and chronic and acute physiological responses to stress in the laboratory. Acute lab stressors will include mental arithmetic, cold pressor and exercise treadmill. Specifically, we will assess cardiovascular and plasma catecholamine reactivity to lab stressors; hemodynamic responses, comprising heart rate, blood pressure, stroke volume, cardiac output, and total peripheral resistance; arterial compliance, and cardiac autonomic nervous system tone using heart rate variability. Laboratory blood pressure patterns will be compared with ambulatory blood pressure monitoring in the naturalistic environment. Possible mediators through which the intervention affects blood pressure (i.e., psychosocial factors, behavioral factors, autonomic tone, CV reactivity and hemodynamic factors) will be investigated standard mediator analyses for intervening variable effects with regression models. The results of this study will provide much needed data on cardiovascular, neuroendocrine, autonomic and behavioral mechanisms by which a stress reduction intervention may lower blood pressure and thereby prevent and treat hypertension in this African American population. The application has several strengths including the expertise of the investigative team, previous extension of the investigator's prior work, a "translational" approach to understanding the underlying biological, behavioral, and psychosocial factors involved, use of measures which are theoretically strong, the randomized controlled study design, and the high likelihood that the study will be successfully completed. However, there are several minor study design issues that all appear remediable. Overall enthusiasm for this application remains high.