An Objective Measure of Physical Activity in the DPPOS: the Accelerometry Ancilla

摘要：最近，包括糖尿病预防计划（DPP）在内的五项临床试验证明了生活方式干预对2型糖尿病预防的有效性。所有这些试验的结果都支持一种生活方式方法（包括体育活动）来预防最初处于糖尿病高风险的个体的2型糖尿病。民进党的独特之处在于它在招募的参与者中具有显著的多样性（种族/种族，年龄和地理）。所有这五项临床试验都使用了一种主观测量方法来评估各自预防工作中的身体活动水平。在原始研究结束时，DPP的身体活动水平在随机分组之间显示出统计学差异。活动问卷在基线时评估的活动水平的部分相关性与空腹和75克口服胰岛素葡萄糖耐量（空腹和负荷后30分钟）、空腹血浆胰岛素原和HbA1c呈显著负相关。然而，在调整体重变化后，这些问卷确定的生活方式组从基线到第2年的身体活动水平变化与糖尿病发病率没有显著相关性。这些发现的一个潜在原因可能部分是由于体育活动问卷本身的测量误差。由于干预导致的身体活动水平的适度变化可能无法用主观测量方法检测到。身体活动问卷在评估低强度和非结构化身体活动方面存在局限性，而这已成为当前干预建议的重点之一。此外，由于活动处方变得更加灵活，允许个人将他们的活动分成更小的部分，因此对身体活动的回忆和主观评估变得更加困难。最后，样本的多样性也给27个地点的准确评估带来了挑战。由于这些原因，在DPP中，为了全面了解体力活动的变化及其影响，人们可能需要使用更精确的客观体力活动测量方法。活动监测器，更具体地说是加速度计，已经成功地在一些干预措施中客观记录了身体活动的变化。加速度计是一种小型活动监测器，通常佩戴在臀部，配备一个电子传感器，可以测量运动的数量和强度，从而收集和存储每天的身体活动模式。由于加速度计测量的身体活动可以被划分为不同强度水平的活动回合，因此可以确定在总运动中花费的时间和在特定强度上花费的时间。我们最近分析了来自国家数据集（NHANES）的体育活动数据，其中我们证明，根据使用的活动评估方式，可以得出两种截然不同的结论。虽然活动问卷的数据表明西班牙裔男性和女性是最不活跃的群体，但在同一时间收集的加速度计数据发现西班牙裔男性和女性都是最活跃的群体。此外，空腹血糖和胰岛素被证明与加速度计活动计数显著相关，但与问卷评估的总每日活动无关。这表明需要通过加速计来观察DPP中的活动。由于干预导致的活动变化可能是微妙的，反映了生活方式的变化，很难通过问卷确定，而且由于DPP人口在种族/种族、年龄和地理位置方面非常多样化，体育活动水平可能太复杂，无法通过回忆来评估。本辅助研究的目的是使用加速度计客观评估所有选择参加下一轮DPP随访研究且尚未转化为糖尿病的DPP参与者的身体活动水平。尽管自最初的试验结束以来，干预的影响似乎已经减弱，但与其他两组相比，生活方式组的糖尿病发病率、心血管疾病和代谢综合征风险因素仍然更好。我们可以合理地假设，这些群体之间的身体活动水平差异也可能是造成这种较好的健康状况的部分原因。此外，在我们确定加速度计数据与来自MAQ活动问卷的报告体力活动之间的关系之后，我们将能够使用该信息指导DPP和DPPOS数据分析，包括由MAQ测量的活动水平（自原始DPP临床试验基线以来一直使用）。这一应用取决于今后D后续行动第二周期的供资情况。公共卫生相关性：本应用程序旨在使用加速度计客观评估所有选择参加下一轮DPP随访研究且尚未转化为糖尿病的DPP参与者的身体活动水平。所有五项使用生活方式干预方法预防2型糖尿病的临床试验都使用了主观测量方法来评估各自工作中的身体活动水平。我们可能再也没有机会在糖尿病预防的随机临床试验中调查这个问题了。因此，我们召集了一个调查小组来开展这个独特的项目。

DESCRIPTION (provided by applicant): An Objective Measure of Physical Activity in the DPPOS: The Accelerometry Ancillary Study Abstract The effectiveness of lifestyle intervention for the prevention of Type2 diabetes has been recently demonstrated in five clinical trials including the Diabetes Prevention Program (DPP). The results of all of these trials support a lifestyle approach (which includes physical activity) to the prevention of Type2 diabetes in individuals that were initially at high risk for diabetes. The uniqueness of the DPP was that it had significant diversity (ethnicity/race, age and geography) among the participants recruited. All of these five clinical trials used a subjective measure to assess physical activity levels in their respective prevention efforts. Physical activity levels in the DPP were shown to be statistically different at the end of the original study between the randomized groups. Partial correlations of activity levels as assessed at baseline by the activity questionnaires were significantly and inversely associated with fasting and 75- g oral glucose tolerance measures of insulin (fasting and 30 minute postload), fasting plasma proinsulin, and HbA1c. Yet, change in physical activity level from baseline to year 2 in the lifestyle arm as determined by theses questionnaires was not significantly related to diabetes incidence after adjustment for weight change. A potential reason for these findings is likely due, in part, to the measurement error of the physical activity questionnaire itself. Modest changes in physical activity levels due to the intervention may not feasibly be detected using subjective measures. Physical activity questionnaires have limitations in assessing low-intensity and unstructured physical activity which have now become part of the focus of current intervention recommendations. Also, as the activity prescription has become more flexible, allowing individuals to split up their activity bouts into smaller pieces, the recall and therefore subjective assessment of physical activity becomes more difficult. Finally, the diversity of the sample also makes accurate assessment across the 27 sites a challenge. For these reasons, in the DPP, to capture the full extent of the physical activity change and its impact, one will likely need to utilize more precise objective measures of physical activity. Activity monitors, more specifically accelerometers, have been successfully used to objectively document physical activity changes in several intervention efforts. The accelerometer is a small activity monitor, typically worn on the hip and is equipped with an electronic sensor that measures both quantity and intensity of movement, resulting in the collection and storage of daily patterns of physical activity. Since physical activity measured by the accelerometer can be partitioned into activity bouts of varying levels of intensity, both the amount of time spent in total movement and the amount of time spent in specific intensities can be determined. We recently analyzed the physical activity data from a national data set (NHANES) in which we demonstrated that two very different conclusions can be drawn in regards to activity ranking of the ethnic groups, depending on which activity assessment is used. Although data from the activity questionnaire identified Hispanic men and women to be among the least active groups, accelerometer data collected around the same time found both Hispanic men and women to be among the most active. In addition, fasting glucose and insulin was shown to be significantly related to accelerometer activity counts but not to total daily activity as assessed by questionnaire. This demonstrates the need to look at activity in the DPP by accelerometer. Since the changes in activity due to the intervention were likely subtle and reflect lifestyle changes hard to determine by questionnaire, and since the DPP population was very diverse in regards to ethnicity/race, age and geographic location, physical activity levels may be too complex to assess by recall. The purpose of this ancillary study is to objectively assess physical activity levels with the use of an accelerometer in all DPP participants that have chosen to participate in the next cycle of the DPP follow-up study and have not yet converted to diabetes. Even though the impact of the intervention appears to have weakened since the end of the original trial, diabetes incidence and cardiovascular disease and metabolic syndrome risk factors continue to be better in the lifestyle group compare to the other two groups. It is reasonable to hypothesize that differences in physical activity levels among the groups may also exist that could be partially responsible for this better health profile. In addition, after we determine the relationship between accelerometer data and reported physical activity derived from the MAQ activity questionnaire, we would be able to use this information to direct DPP and DPPOS data analyses involving activity levels measured by the MAQ (which has been utilized since baseline of the original DPP clinical trial). This application is contingent on the future funding of the second cycle of the D follow-up. PUBLIC HEALTH RELEVANCE: This application aims to objectively assess physical activity levels with the use of an accelerometer in all DPP participants that have chosen to participate in the next cycle of the DPP follow-up study, and have not yet converted to diabetes. All five clinical trials that utilized a lifestyle intervention approach in the prevention of Type 2 diabetes used a subjective measure to assess physical activity levels in their respective efforts. We will likely never have the opportunity to investigate this question in a randomized clinical trial of diabetes prevention again. Therefore, we have convened a team of investigators to carry out this unique project.