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

描述(申请人提供)：老年美国人是增长最快的年龄段，也是体力活动最少的年龄段。体力活动(PA)已被证明可以降低心血管事件、功能障碍、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“中等到剧烈的体力活动”上，但越来越多的证据表明，无论PA水平如何，整体久坐的生活方式可能与心血管健康呈负相关。目前关于PA对老年人健康结局的影响的研究主要有四个方面：1)不准确的测量方法；2)缺乏独立于PA的久坐行为对健康影响的数据；3)缺乏对PA的剂量-反应关系的详细评估；4)缺乏关于PA如何减轻靶器官损害的数据，这经常是公开的心血管疾病的先兆。这项应用的具体目的如下：目的1.在以社区为基础的弗雷明翰心脏研究的3000名老年白人和非白人参与者(平均年龄75岁)中，用全方位加速度计在5-7天的时间内客观地测量PA和久坐行为的强度和模式，并将这些测量与心血管疾病危险因素联系起来。目的2.客观测量的静坐行为和强度/模式与心脏结构和功能(通过超声心动图评估)、大动脉僵硬(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)的测量相关联。我们将把总的PA和久坐行为与这些靶器官损害的指标联系起来。目的3.前瞻性地将客观测量的PA和久坐行为的强度和模式与心血管事件(冠心病、中风和心力衰竭)、痴呆症和全因死亡率联系起来。我们应用于分析在持续纵向监测下以前登记的大型老龄化多种族社区队列中现有的加速度计数据，将弥合我们目前关于PA的健康益处(强度和模式)以及久坐生活方式与老年人健康结果的关系的基本和关键差距。我们将阐明PA对靶器官损害的影响，并建立科学资源，为未来公共卫生建议和老年人PA的临床指南提供证据基础。

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.