A Mechanistic Trial of Dietary Sodium Reduction on Vascular Structure and Function in African Americans

膳食钠减少对非裔美国人血管结构和功能的机制试验

• 批准号: 10365668
• 负责人: Katherine Teresa Mills
• 金额: $ 68.68万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-17 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10365668
• 关键词: Academy; Adherence; African American; African American population; Albuminuria; Ambulatory Blood Pressure Monitoring; Area; Behavior Therapy; Blood Pressure; Blood Vessels; Cardiac; Cardiovascular Diseases; Cardiovascular system; Chronic Disease; Chronic Kidney Failure; Clinic Visits; Clinical; Cohort Studies; Control Groups; Diet; Dietary Sodium; Dietitian; Disease Outcome; EFRAC; Endothelium; Etiology; Event; Exclusion Criteria; Heart; Heart Atrium; Hour; Hypertension; Impairment; Incidence; Intake; Intention; Intervention; Knowledge; Left; Left Ventricular Ejection Fraction; Left Ventricular Hypertrophy; Left Ventricular Mass; Measures; Mediating; Medicine; Monitor; Observational Study; Organ; Outcome; Outcome Study; Participant; Patients; Physiologic pulse; Play; Potassium; Protocols documentation; Quality Control; Randomized; Randomized Controlled Trials; Recording of previous events; Reporting; Risk Factors; Role; Side; Sodium; Standardization; State Medicine; Structure; Testing; Ventricular; Woman; aged; arterial stiffness; blood pressure elevation; blood pressure reduction; cardiac magnetic resonance imaging; cardiovascular disorder prevention; cardiovascular disorder risk; cardiovascular risk factor; clinical risk; clinically significant; dietary; endothelial dysfunction; high risk; improved; indexing; men; mortality; primary outcome; recruit; renal damage; secondary analysis; targeted biomarker

Project Summary High dietary sodium intake increases risk of cardiovascular disease (CVD) independent of established risk factors, including blood pressure (BP). Non-BP mediated mechanisms underlying the increased risk of CVD associated with dietary sodium intake are not well understood, but observational studies suggest direct target organ damage in the heart and vasculature might play an important role. Little evidence exists from randomized controlled trials (RCTs) on target organ effects of dietary sodium reduction, and the National Academy of Medicine has recommended future research to “test the effects of different sodium intake levels on endothelial and vascular function” in order to “to better characterize the relationship between sodium intake and chronic disease”. Further, no RCTs have been powered to test the effect of dietary sodium reduction on subclinical cardiovascular structure and function in African Americans, who are more sensitive to dietary sodium intake and at higher risk for CVD. The overall objective of the proposed mechanistic trial is to test the effect of dietary sodium reduction on cardiac and vascular structure and function. Specifically, the proposed trial will test whether dietary sodium reduction (targeting a dietary sodium intake of <2,300 mg/day) will improve left ventricular mass index (LVMI), left ventricular global longitudinal strain (LVGLS), carotid-femoral pulse wave velocity (cfPWV), and flow-mediated dilation (FMD) compared to usual intake. Additionally, we will test whether this effect is independent from BP reduction. We will recruit 240 African Americans with elevated BP or hypertension from the greater New Orleans area and randomly assign them to a dietitian-led behavioral intervention aimed at decreasing dietary sodium intake to <2,300 mg/day for 12 months or to a usual diet. Study outcomes, including cardiac magnetic resonance imaging (CMR)-determined LVMI and LVGLS, cfPWV, and FMD, will be measured at baseline, 6-month, and 12-month clinic visits using standardized protocols with stringent quality control. These outcomes are validated biomarkers for target organ damage and predict the risk of clinical CVD events. In primary analyses, the effect of sodium reduction on each subclinical CVD endpoint will be compared between the sodium reduction and usual diet groups according to the intention-to- treat principle without adjusting for covariates. In secondary analyses, changes in ambulatory and clinical BP will be adjusted to assess the BP-independent effect of dietary sodium reduction on each subclinical CVD endpoint. The proposed trial has 85% statistical power to detect a clinically significant difference in changes of the four co-primary outcomes (10 g/m2 in LVMI, 1.3% in LVGLS, 0.9 m/s in cfPWV, and 1.1% in FMD) over 12 months between the two groups at a 2-sided significance level of 0.0125 (0.05/4). This study is the first RCT to test the effect of dietary sodium reduction on subclinical CVD endpoints in African Americans. Findings from this trial will fill the knowledge gap of the underlying mechanisms of dietary sodium intake on CVD risk and provide further evidence on sodium reduction for CVD prevention.

项目摘要 高膳食钠摄入量增加心血管疾病（CVD）的风险，与已确定的风险无关 包括血压（BP）。CVD风险增加的非BP介导机制 与膳食钠摄入量的关系尚不清楚，但观察性研究表明， 心脏和脉管系统中的器官损伤可能起重要作用。几乎没有证据表明 关于饮食钠减少对靶器官影响的随机对照试验（RCT），以及国家 医学院建议未来的研究“测试不同钠摄入水平对 内皮和血管功能”，以“更好地表征钠摄入量之间的关系 慢性病”。此外，没有RCT能够检验膳食钠减少对 非裔美国人的亚临床心血管结构和功能，他们对饮食更敏感， 钠摄入量和心血管疾病的风险更高。拟议机制试验的总体目标是测试 膳食钠减少对心血管结构和功能影响具体而言，建议 试验将测试饮食钠减少（目标是饮食钠摄入量<2，300 mg/天）是否会 改善左心室质量指数（LVMI）、左心室整体纵向应变（LVGLS）、颈动脉-股动脉 脉搏波速度（cfPWV）和血流介导的扩张（FMD）与通常摄入量相比。此外，我们将 测试这种效果是否独立于BP降低。我们将招募240名非裔美国人， 血压或高血压从大新奥尔良地区，并随机分配他们到一个营养师主导的行为 干预措施旨在将膳食钠摄入量降低至<2，300 mg/天，持续12个月或正常饮食。 研究结局，包括心脏磁共振成像（CMR）确定的LVMI和LVGLS、cfPWV， 和FMD，将在基线、6个月和12个月门诊访视时使用标准化方案进行测量， 严格的质量控制。这些结果是靶器官损伤的有效生物标志物，可预测 临床CVD事件的风险。在主要分析中，钠减少对每种亚临床CVD的影响 根据意向，将在钠减少组和常规饮食组之间比较终点， 治疗原则，不调整协变量。在次要分析中，动态和临床血压的变化 将进行调整，以评估饮食钠减少对每种亚临床CVD的BP独立影响 终点。拟议的试验具有85%的统计功效，可检测到 12岁以上的4个共同主要结局（LVMI <10 g/m2，LVGLS <1.3%，cfPWV <0.9 m/s，FMD <1.1%） 两组之间的时间间隔为0.0125（0.05/4）的双侧显著性水平。这项研究是第一个RCT， 测试饮食钠减少对非裔美国人亚临床CVD终点的影响。的结果 这项试验将填补膳食钠摄入对心血管疾病风险的潜在机制的知识空白， 提供了进一步的证据，减少钠的CVD预防。