Accuracy of Physical Activity Measures in Cancer Studies

描述（由申请人提供）：流行病学研究中体力活动评估所固有的方法学挑战引入了测量误差，限制了我们对体力活动在降低癌症和其他疾病风险中的作用的理解。本提案的主要目标是确定和量化与两个自我管理的体力活动（PA）问卷相关的测量误差，该问卷用于评估两项正在进行的癌症队列研究（癌症流行病学研究后的生活，由NCI资助，以及加州男性健康研究，由加州癌症研究计划资助）中的近期活动。为了实现这一目标，我们建议进行一项验证研究，包括比较两个测试问卷与1）14天的体力活动日记（2个7天周期，间隔5-6个月）; 2）14天的加速度计记录，与PA日记同时进行; 3）根据次最大分级运动跑步机测试确定的有氧能力;和4）身体尺寸测量（身体质量指数、来自生物电阻抗的%身体脂肪和腰围）。验证研究还将包括对两份问卷的2-4周重测重复性的评价。研究参与者将从北方加州Kaiser Permanente（KP）癌症登记处和一般会员档案中随机抽取，将包括400名年龄为45-65岁、在招募前24-36个月诊断为乳腺癌或前列腺癌的女性和男性，以及400名年龄相似但无癌症史的女性和男性。预计抽样将反映金伯利进程成员的种族/族裔多样性。此外，我们建议开发一个应用程序的手持计算机（个人数字助理或PDA），将用于PA日记的收集和管理。我们将在验证研究之前的一项初步研究中评价PDA上收集的PA日记与传统纸质和笔式日记的可比性。在试点研究中，从验证研究中使用的同一抽样框架中随机抽取的50名男性和女性将在连续3周的每一周中记录他们的活动，为期4天，其中一半使用PDA进行两个阶段，另一半使用纸和笔进行一个阶段，另一半则相反。试点研究的参与者还将完成认知访谈，以提供对PDA软件的可用性的见解，以及通过两份测试问卷回忆体力活动所需的思维过程。将确定并量化问卷中的测量误差来源，并将用于校正测量误差的统计方法应用于母研究，以估计与体力活动相关的疾病（乳腺癌复发或前列腺癌事件）风险。由于验证将在一个大的，多样化的，随机选择的样本中进行，研究结果可能会推广到身体活动和癌症的其他研究，并可能对身体活动和其他健康结果的研究具有广泛的适用性。

DESCRIPTION (provided by applicant): Methodological challenges inherent in the assessment of physical activity in epidemiological studies introduce measurement errors that limit our understanding of the role of physical activity in reducing the risk of cancer and other diseases. The primary goal of this proposal is to identify and quantify the measurement error associated with two self administered physical activity (PA) questionnaires used to assess recent activity in two on-going cancer cohort studies (Life After Cancer Epidemiology Study, funded by the NCI, and the California Men's Health Study, funded by the California Cancer Research Program). To achieve this goal, we propose to conduct a validation study involving comparisons of the two test questionnaires with 1) 14 days of physical activity diaries (2 7-day periods, 5-6 months apart); 2) 14 days of accelerometer recordings, simultaneous with the PA diaries; 3) aerobic capacity as determined from a sub-maximal graded exercise treadmill test; and 4) body size measurements (body mass index, % body fat from bioelectric impedance, and waist circumference). The validation study will also include evaluation of 2-4 week test-retest repeatability of the two questionnaires. The study participants will be randomly drawn from the Northern California Kaiser Permanente (KP) Cancer Registry and general membership files and will consist of 400 women and men, ages 45-65, diagnosed with breast or prostate cancer 24-36 months prior to recruitment, and 400 women and men of similar age but with no history of cancer. The sample is expected to reflect the racial/ethnic diversity of the KP membership. In addition, we propose to develop an application program for a hand-held computer (personal digital assistant or PDA) that will be used for the collection and management of the PA diaries. We will evaluate the comparability of the PA diaries collected on the PDAs with traditional paper and pen diaries in a pilot study prior to the validation study. For the pilot study, 50 men and women, randomly drawn from the same sampling frame to be used in the validation study, will record their activities for a 4-day period in each of 3 consecutive weeks, with half using PDAs for two of the periods and paper and pen for one period, and the other half doing the reverse. The pilot study participants will also complete a cognitive interview to provide insights into the usability of the PDA software and the thought processes required in the recall of physical activity by the two test questionnaires. Sources of measurement error in the questionnaires will be identified and quantified, and statistical methods for adjusting for measurement error will be applied to the parent studies to estimate the risk of disease (breast cancer recurrence or incident prostate cancer) associated with physical activity. Because the validation will be conducted in a large, diverse, randomly selected sample, the findings may be potentially generalizable to other studies of physical activity and cancer, and may have broad applicability for studies of physical activity and other health outcomes as well.