Physical Activity, Cardiometabolic Risk, and Target-Organ Damage in Older Adults

描述（由申请人提供）：美国老年人是增长最快的年龄组，也是身体活动最少的年龄组。体力活动（PA）已被证明可以降低CVD事件、功能残疾、认知能力下降和全因死亡率的风险。PA指南和大多数流行病学研究都集中在“中度到剧烈的体力活动”上，但有新的证据表明，无论PA水平如何，久坐不动的生活方式可能与心血管健康存在不良关系。目前关于PA对老年人健康结果影响的研究主要局限于4个方面：1）测量方法不准确; 2）缺乏与PA无关的久坐行为对健康影响的数据; 3）缺乏对PA“剂量-反应”关系的详细评估; 4）缺乏关于PA如何减轻靶器官损伤的数据，这是明显CVD的常见前兆。本申请的具体目的如下：目的1.在基于社区的心脏病研究（平均年龄75岁）的3000名老年白色和非白色参与者中，采用全方位加速度计在5-7天内客观测量PA和久坐行为的强度和模式分布特征;并将这些测量结果与CVD风险因素相关联。目标2.将客观测量的久坐行为和PA强度/模式与心脏结构和功能（通过超声心动图评估）、大动脉僵硬度（通过压平眼压计）、脑结构（通过MRI）和认知功能以及肾功能（24小时白蛋白排泄和估计的肾小球滤过率）的测量结果相关联。我们将把总PA和久坐行为与靶器官损伤的这些指标联系起来。目标3：前瞻性地将客观测量的PA和久坐行为的强度和模式与CVD事件（冠心病、中风和心力衰竭）、痴呆和全因死亡率联系起来。我们的应用程序来分析现有的加速度数据在以前登记的大型老龄化多种族社区为基础的队列连续纵向监测将弥合一个根本和关键的差距，在我们目前的知识对PA的健康益处（强度和模式）和久坐不动的生活方式与老年人的健康结果的关系。我们将阐明PA对靶器官损伤的影响，并建立一个科学资源，这将有助于为未来的公共卫生建议和老年人PA的临床指南的证据基础。

DESCRIPTION (provided by applicant): Older Americans are the most rapidly growing age group, and also the least physically active. Physical activity (PA) has been shown to reduce the risk of CVD events, functional disability, cognitive decline, and all-cause mortality. PA guideline and most epidemiologic studies have focused on 'moderate-to-vigorous physical activity', but there is emerging evidence that an overall sedentary lifestyle may be adversely associated with cardiovascular health regardless of PA levels. Current research on the impact of PA on health outcomes in older adults is limited in 4 major ways: 1) inaccurate measurement methodology; 2) lack of data on health effects of sedentary behavior, independent of PA; 3) missing detailed assessment of PA 'dose-response' relations; 4) scant data on how PA mitigates target organ damage that is a frequent precursor of overt CVD. The specific aims of this application are as follows: Aim 1. To characterize the distributions of intensity and patterns of both PA and sedentary behavior, measured objectively with an omni-directional accelerometer over a 5-7 day period, in 3000 older white and non-white participants in the community-based Framingham Heart Study (mean age 75 years); and to relate these measures to CVD risk factors. Aim 2. To relate objectively measured sedentary behavior and intensity/patterns of PA to measures of cardiac structure and function (assessed by echocardiography), large artery stiffness (via applanation tonometry), brain structure (via MRI) and cognitive function, and renal function (24-hour albumin excretion and estimated glomerular filtration rate). We will relate total PA and sedentary behavior to these measures of target organ damage. Aim 3. To relate intensity and patterns of objectively measured PA and sedentary behavior to incident CVD events (coronary heart disease, stroke, and heart failure), dementia and all-cause mortality prospectively. Our application to analyze extant accelerometry data in a previously enrolled large aging multiethnic community-based cohort under continuous longitudinal surveillance will bridge a fundamental and critical gap in our current knowledge regarding the health benefits of PA (intensity and patterns) and the relationship of a sedentary lifestyle with health outcomes in older people. We will elucidate the impact of PA on target organ damage, and establish a scientific resource that will contribute to the evidence base for future public health recommendations and clinical guidelines for PA in older adults.