Measurement of Sedentary Behavior in African American Adults

描述（由申请人提供）：久坐的生活方式已被证明是心血管疾病风险标志物（Jakes et al ., 2003）和心血管疾病发展的独立危险因素（Sidney et al ., 1996）。尽管存在健康风险，但据估计，美国人久坐的比例在30%到40%之间（Sidney et al, 1996; Yancey et al, 2004）。研究表明，非裔美国人比白种人花更多的时间从事久坐行为（Sidney et al ., 1996； USDHHS, 2001）。一份报告显示，近60%的非裔美国人过着久坐不动的生活方式（Karter et al, 1998）。非裔美国人患有各种各样的健康问题，包括肥胖、高血压和糖尿病。看来，久坐行为是影响非裔美国人健康状况的一个因素。因此，非裔美国成年人是研究久坐行为与心血管疾病关系的主要目标，也是减少久坐行为干预的理想目标。久坐行为传统上是通过自我报告来评估的。这些自我报告的测量受到许多潜在问题的影响，包括回忆偏差，仅在闲暇时间进行评估，以及缺乏对客观测量的验证。因此，有必要对久坐行为进行客观的测量。加速度计提供了一种客观测量久坐行为的方法。目前，已经为成人制定了轻度、中度和剧烈运动的阈值，但还没有用于定义久坐行为的阈值。Matthews（2005）表达了对久坐行为的成人分界点的需求。这项研究的主要目的有三个。这项研究的主要目的之一是制定成年人久坐行为的客观阈值。该研究的第二个目的是开发并验证久坐行为的自我报告测量方法。该研究的第三个目的是开发和评估旨在减少成年人体育活动的干预措施的有效性。所有这些目标都将在非裔美国成年人的样本中实现。为了确定久坐行为的分割线，每位参与者在进行一系列活动时都要佩戴加速度计，这些活动从久坐到适度的身体活动，包括休息、看电视、坐着、读书和在跑步机上行走。为了开发久坐行为的自我报告测量，将从《体育活动纲要》中提取低于1.5 METs的活动（Ainsworth等人，2000）。该测量将在参与者佩戴加速度计的情况下进行，为期两周，一周，以建立自我报告测量的重测信度和标准效度。客观定义的久坐行为与健康结果之间的关系将通过将切割点应用于杰克逊心脏研究（JHS）中使用的加速度计来评估。JHS是一项针对非裔美国成年人心血管疾病发病前的流行病学研究。超过400人参加了饮食和体育活动子研究，该研究要求他们在基线时佩戴加速度计。在这项初步研究之后，将计划进行第二项研究，旨在减少非裔美国成年人的久坐行为。这将涉及到招募新的参与者样本。这些成年人将从南方的一个大城市招募并被随机分配到干预组和对照组。社会认知理论指导6个月干预计划的发展。对照组将在同一时间段内参加几次会议，重点是提供有关体育活动的信息。主要的结果变量是久坐行为的分钟数，将通过加速度计进行评估。

DESCRIPTION (provided by applicant): A sedentary lifestyle has been shown to be an independent risk factor for markers of cardiovascular disease risk (Jakes et al, 2003) and the development of cardiovascular diseases (Sidney et al, 1996). Despite the health risks, estimates of the percentage of Americans who are sedentary range from 30 to 40% (Sidney et al, 1996; Yancey et al, 2004). It has been shown that African Americans spend more time engaged in sedentary behaviors than do their Caucasian counterparts (Sidney et al, 1996; USDHHS, 2001). One report has shown that nearly 60% of African American men and women live a sedentary lifestyle (Karter et al, 1998). African Americans suffer disproportionately from various health conditions, including obesity, hypertension, and diabetes. It appears that sedentary behavior is a contributing factor to the health status of African Americans. Thus, African American adults are prime targets for studying the relationship between sedentary behavior and cardiovascular disease, and are also ideal targets for intervention designed to decrease sedentary behavior. Sedentary behavior has traditionally been assessed via self-report. These self-reported measures are subject to a number of potential problems, including recall bias, assessment only during leisure time, and lack of validation against an objective measure. Thus, there is a need for an objective measure of sedentary behavior. Accelerometers provide a way to objectively measure sedentary behavior. Currently, thresholds for light, moderate and vigorous activity have been developed for adults, yet there are no thresholds that are used to define sedentary behavior. The need for adult cut-points for sedentary behavior was expressed Matthews (2005). The primary aims for the study are threefold. One of the primary aims of the study is to develop objective thresholds of sedentary behavior in adults. The second aim of the study is to develop and validate a self-report measure of sedentary behavior. A third aim of the study is to develop and assess the effectiveness of an intervention designed to reduce physical activity in adults. All of these aims will be achieved in samples of African American adults. To establish cut-points for sedentary behavior, each participant will wear an accelerometer while engaging in a series of activities ranging from sedentary to moderate physical activity, including resting, watching TV, sitting a desk, reading a book, and walking on a treadmill. In order to develop a self-report measure of sedentary behavior, activities less than 1.5 METs will be extracted from the Compendium of Physical Activities (Ainsworth et al, 2000). The measure will be administered while participants wear an accelerometer for two, one-week periods in order to establish the test-retest reliability and criterion validity of the self-report measure. The relationship between objectively defined sedentary behavior and health outcomes will be assessed by applying the cut-points to the accelerometers that were used in the Jackson Heart Study (JHS). The JHS is an epidemiological study of the antecedents of cardiovascular disease in African American adults. Over four hundred of those enrolled participated in the Diet and Physical Activity Substudy, which required that they wear an accelerometer at baseline. Following this initial study, a second study will be planned that is designed to decrease sedentary behavior in African American adults. This will involve recruiting a new sample of participants. These adults will be recruited from a large Southern city and will be randomly assigned to either the intervention group or the control group. The Social Cognitive Theory guides the development of the 6-month intervention program. The control group will attend several sessions over this same time frame that focus on providing information on physical activity. The primary outcome variable, minutes of sedentary behavior, will be assessed via accelerometers.