Centre for Physical Activity and Nutrition, Auckland University of Technology, Auckland, New Zealand.
Prev Med. 2010 Nov;51(5):357-60. doi: 10.1016/j.ypmed.2010.08.010. Epub 2010 Sep 9.
To investigate the utility of a variety of Actical accelerometer count thresholds for determining sitting time in a sample of office workers.
Data were collected from 21 participants in Auckland, New Zealand, between December 2009 and January 2010. Participants wore a hip-mounted Actical accelerometer and thigh-mounted activPAL inclinometer (criterion) for a 48-h period. Raw inclinometer and accelerometer data for each 15s epoch of wear time were matched by date and time. Candidate accelerometer count thresholds for sitting classification were compared with the criterion measure using receiver operating characteristic analyses. Agreement in sitting time classification was determined using Bland-Altman methodology.
Significant differences in area under the curve (AUC) values by threshold criteria were found (p<0.001). A threshold of 0 counts provided the highest combined sensitivity and specificity (AUC 0.759, 95%CI 0.756, 0.761). The 95% limits of agreement for time spent sitting were wide, at 328min (range -30.8, 297.5).
A threshold of 0 counts/15s epoch with Actical accelerometers is likely to yield the most accurate quantification of sitting in office-based workers, however the wide limits of agreement found indicate limited utility of this threshold to accurately distinguish sitting time in office-based workers.
探讨 Actical 加速度计的多种计步阈值在确定办公人员坐时的应用价值。
2009 年 12 月至 2010 年 1 月期间，在新西兰奥克兰市招募了 21 名参与者。参与者佩戴髋部 Actical 加速度计和大腿部 activPAL 倾斜计（金标准）进行为期 48 小时的测量。通过日期和时间匹配每个佩戴 15 秒的原始倾斜计和加速度计数据。使用接收者操作特性分析比较候选加速度计计步阈值与金标准测量的坐分类。使用 Bland-Altman 方法确定坐时分类的一致性。
按阈值标准发现曲线下面积（AUC）值存在显著差异（p<0.001）。0 计数阈值提供了最高的综合敏感性和特异性（AUC 0.759，95%CI 0.756，0.761）。坐时的 95%一致性界限很宽，为 328 分钟（范围 -30.8，297.5）。
对于基于办公室的工作人员，Actical 加速度计的 0 计数/15 秒阈值可能会产生最准确的坐时定量，但发现的广泛一致性界限表明该阈值在准确区分基于办公室的工作人员的坐时方面的应用价值有限。
