Lupolt Sara N, Lyu Qinfan, Zhang Guofeng, Wang Jiahao, Tang Stacey, Cho Jamie, Huynh Christina, Yuille Alan, Voegtline Kristin, Nachman Keeve E
Department of Environmental Health & Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
J Expo Sci Environ Epidemiol. 2025 Aug 13. doi: 10.1038/s41370-025-00800-3.
Microactivity rates, including hand- and object-to-mouth contacts, are inputs for modeling children's exposure to chemicals in soil and dust and from toys. EPA's confidence in its current recommended microactivity frequency estimates for use in exposure assessments is low.
We aimed to quantify children's hand- and object-to-mouth microactivities using a novel computer vision method and explored differences by lifestage and fine and gross motor development.
We recorded 20-minute videos of 61 children aged 6 to ≤18 months playing in their homes under two play contexts. We employed a novel computer vision approach that uses multiview video to estimate 3D body keypoints and measure hand-to-mouth distances, enabling quantification of each child's hand-and object-to-mouth contact without the need for human coders. We explored differences in the frequency and duration of microactivity contacts by age and motor development.
We observed at least one instance of a microactivity event (i.e., hand- or object-to-mouth contact) among 41 of the 61 participants observed. The median rate of object-to-mouth contacts (23 contacts/hour) was greater than hand-to-mouth contacts (6 contacts/hour). We did not observe significant differences in the frequency of either hand-to-mouth and object-to-mouth contacts by age or motor development, but we did observe greater variation in object-to-mouth contacts than previously reported. The median durations of hand- and object-to-mouth contact were 0.24 min/hour and 1.57 min/hour, respectively.
Our observed rates of microactivities are comparable and in some cases, less than the current EPA central tendency estimates recommended for use in risk assessments. Our high-end (95th percentile) estimate for object-to-mouth contacts, however, underscores the need for better characterization of population variability in order to protect the most highly exposed children.
We apply a novel computer vision algorithm to quantify the microactivity frequencies and durations of 61 children 6 to ≤18 months old. We examine differences in these frequencies and durations by child lifestage and motor development. Demonstration of this method paves the way for future, larger studies that observe children for longer durations to develop confident estimates of population variability in microactivity behaviors. These and future data could inform analyses in support of the revision of EPA recommendations for children's soil and dust ingestion rates.
微活动率，包括手与嘴以及物体与嘴的接触，是模拟儿童通过土壤、灰尘以及玩具接触化学物质的输入参数。美国环境保护局（EPA）对其目前推荐用于暴露评估的微活动频率估计值的信心较低。
我们旨在使用一种新颖的计算机视觉方法对儿童手与嘴以及物体与嘴的微活动进行量化，并探讨不同生命阶段以及精细和粗大运动发育之间的差异。
我们记录了61名年龄在6至18个月之间的儿童在两种玩耍场景下于家中玩耍20分钟的视频。我们采用了一种新颖的计算机视觉方法，该方法使用多视角视频来估计三维身体关键点并测量手到嘴的距离，从而能够在无需人工编码的情况下对每个儿童的手与嘴以及物体与嘴的接触进行量化。我们探讨了微活动接触的频率和持续时间在年龄和运动发育方面的差异。
在观察的61名参与者中，有41人至少出现了一次微活动事件（即手与嘴或物体与嘴的接触）。物体与嘴接触的中位数频率（每小时23次接触）高于手与嘴接触的频率（每小时6次接触）。我们未观察到手与嘴以及物体与嘴接触的频率在年龄或运动发育方面存在显著差异，但我们确实观察到物体与嘴接触的变异性比先前报道的更大。手与嘴以及物体与嘴接触的中位数持续时间分别为每小时0.24分钟和1.57分钟。
我们观察到的微活动率具有可比性，在某些情况下，低于目前EPA推荐用于风险评估的中心趋势估计值。然而，我们对物体与嘴接触的高端（第95百分位数）估计强调了更好地表征人群变异性的必要性，以便保护暴露程度最高的儿童。
我们应用一种新颖的计算机视觉算法对61名6至18个月大儿童的微活动频率和持续时间进行量化。我们研究了这些频率和持续时间在儿童生命阶段和运动发育方面的差异。该方法的展示为未来更大规模的研究铺平了道路，这些研究将对儿童进行更长时间的观察，以得出对微活动行为人群变异性的可靠估计。这些数据以及未来的数据可为支持修订EPA关于儿童土壤和灰尘摄入量建议的分析提供信息。
