Establishing best practices for the use of accelerometer measured ambient light sensor data to assess children's outdoor time

摘要 花时间在户外增加儿童的体力活动并促进与自然的接触，这 已被证明对儿童的心理、认知和行为健康有积极的好处。然而， 户外时间很难量化，大多数研究依赖于自我或照顾者报告的户外时间。一 解决方案是使用配备环境光传感器技术的加速度计。光传感器提供了一种 可用于客观量化儿童户外时间的光线曝光量(即勒克斯值)的估计值。 尽管加速计的使用无处不在，但大多数研究人员并没有利用这一工具。中的 使用环境光数据的研究，分析方法各不相同。具体地说，研究使用了 不同的勒克斯切割点来区分室内和室外时间，并没有考虑放置 加速度计(即臀部与手腕佩戴)或由于季节性或天气条件造成的潜在误差。 因此，该项目的目标是开发和传播一套最佳做法，用于分析 加速度计得出的环境光数据，以便客观评估 孩子们。拟议的项目将分析来自NHLBI资助的两项干预试验的次要数据，这些试验旨在 在托儿环境中促进体力活动。这两项试验都包括环境中的加速度计数据 启用光传感器以及来自环境和政策评估和观察(EPAO)的数据 工具，这是一种观察性测量，包含儿童保育日的详细时间戳数据，包括室内 和户外时间。在目标1中，将协调加速度计数据，以便于比较HIP-和 然后结合相应的EPAO数据。在目标2中，接收器操作员 特征曲线分析将用来确定最佳勒克斯切割点，以区分室内和 室外时间，将加速度计勒克斯值与EPAO记录的室内和室外时间进行比较。 然后，我们将比较确定的勒克斯切点在区分腕部和手腕的户外时间方面的表现。 臀部磨损的加速度计。最后，我们将比较季节性和不同天气条件(即， 阴天与晴天相比)会影响勒克斯读数。在目标3中，我们将客观地考察两者之间的联系 使用新开发的分析方法测量儿童在照看儿童时的户外时间和体力活动 指导方针。为了促进实地的一致性，我们将通过制定 为其他研究人员提供的开放源代码，可应用于现有的数据集和存储库 加速度计数据。总体而言，该项目将解决评估幼儿的关键测量差距 体力活动和户外时间。改进户外时间的测量将进一步增加对 户外活动对健康的影响，帮助确定在获得 户外活动，并为促进青少年户外活动的政策法规提供支持。

ABSTRACT Spending time outdoors increases children’s physical activity and promotes engagement with nature, which has been shown to have positive benefits on children’s mental, cognitive, and behavioral health. However, outdoor time is difficult to quantify, with most studies relying on self- or caregiver-reported outdoor time. One solution is to use accelerometers equipped with ambient light sensor technology. The light sensor delivers an estimate of light exposure (i.e., lux values) that can be used to objectively quantify children’s outdoor time. Despite the ubiquitous use of accelerometers, most researchers have not taken advantage of this tool. Of the studies that have used ambient light data, analytic approaches have varied. Specifically, studies have used different lux cut points to distinguish between indoor and outdoor time, and have not considered placement of the accelerometer (i.e., hip vs. wrist worn) or the potential error due to seasonality or weather conditions. Therefore, the objective of this project is to develop and disseminate a set of best practices for analyzing accelerometer-derived ambient light data in order to provide an objective assessment of outdoor time in children. The proposed project will analyze secondary data from two NHLBI funded intervention trials targeting physical activity promotion in the child care setting. Both trials included accelerometer data with the ambient light sensor enabled as well as data from the Environment and Policy Assessment and Observation (EPAO) tool, an observational measure that contains detailed time stamped data of the child care day including indoor and outdoor time. In Aim 1, accelerometer data will be harmonized to facilitate comparisons between hip- and wrist-worn devices and then combined with the corresponding EPAO data. In Aim 2, receiver operator characteristic curve analysis will be used to identify the optimal lux cut point to distinguish between indoor and outdoor time, comparing accelerometer lux values to the documented indoor and outdoor time from the EPAO. Then, we will compare how well the identified lux cut point performs in distinguishing outdoor time in wrist vs. hip worn accelerometers. Finally, we will compare how seasonality and different weather conditions (i.e., cloudy vs. clear days) affect lux readings. In Aim 3, we will examine the association between objectively measured outdoor time and children’s physical activity while at child care using the newly developed analytic guidelines. In order to promote consistency in the field, we will disseminate the best practices by developing open source code for other researchers that can be applied to existing datasets and repositories of accelerometer data. Overall, this project will address key measurement gaps in assessing young children’s physical activity and outdoor time. Improving measurement of outdoor time will further add to research into the health impact of spending time outdoors, aid in the identification of disparities regarding access to the outdoors, and provide support for policies and regulations promoting youth outdoor time.