Allied Health & Human Performance, Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, Australia.
Murdoch Children's Research Institute, Parkville, Australia.
J Bone Miner Res. 2020 Dec;35(12):2393-2403. doi: 10.1002/jbmr.4143. Epub 2020 Sep 23.
Optimization of children's activity behaviors for skeletal health is a key public health priority, yet it is unknown how many hours of moderate to vigorous physical activity (MVPA), light physical activity (LPA), sedentary behavior, or sleep constitute the best day-the "Goldilocks Day"-for children's bone structure and function. To describe the best day for children's skeletal health, we used data from the cross-sectional Child Health CheckPoint. Included participants (n = 804, aged 10.7 to 12.9 years, 50% male) underwent tibial peripheral quantitative CT to assesses cross-sectional area, trabecular and cortical density, periosteal and endosteal circumference, polar moment of inertia, and polar stress-strain index. Average daily time-use composition (MVPA, LPA, sedentary time, and sleep) was assessed through 8-day, 24-hour accelerometry. Skeletal outcomes were regressed against time-use compositions expressed as isometric log-ratios (with quadratic terms where indicated), adjusted for sex, age, pubertal status, and socioeconomic position. The models were used to estimate optimal time-use compositions (associated with best 5% of each skeletal outcome), which were plotted in three-dimensional quaternary figures. The center of the overlapping area was considered the Goldilocks Day for skeletal health. Children's time-use composition was associated with all skeletal measures (all p ≤ 0.001) except cross-sectional area (p = 0.72). Days with more sleep and MVPA, less sedentary time, and moderate LPA were beneficially associated with skeletal measures, except cortical density, which was adversely associated. The Goldilocks daily time-use composition for overall skeletal health was center (range): 10.9 (10.5 to 11.5) hours sleep; 8.2 (7.8 to 8.8) hours sedentary time; 3.4 (2.8 to 4.2) hours LPA, and 1.5 (1.3 to 1.5) hours MVPA. Estimated optimal sleep duration is consistent with current international guidelines (9 to 11 hours), while estimated optimal MVPA exceeds recommendations of at least 60 min/d. This first study to describe optimal durations of daily activities for children's skeletal health provides evidence to underpin guidelines. © 2020 American Society for Bone and Mineral Research (ASBMR).
优化儿童的活动行为以促进骨骼健康是公共卫生的重点之一，但目前尚不清楚儿童骨骼结构和功能的最佳一天（“黄金日”）需要多少小时的中等到剧烈体力活动（MVPA）、低强度体力活动（LPA）、久坐行为或睡眠。为了描述儿童骨骼健康的最佳一天，我们使用了来自横断面儿童健康检查点的数据。纳入的参与者（n=804，年龄 10.7 至 12.9 岁，50%为男性）接受了胫骨外周定量 CT 检查，以评估横截面积、小梁和皮质密度、骨膜和骨髓腔周长、极转动惯量和极应变指数。通过 8 天 24 小时加速度计评估平均日常时间利用组成（MVPA、LPA、久坐时间和睡眠）。骨骼结果与时间利用组成呈等比对数（如有需要，还包括二次项）回归，调整性别、年龄、青春期状态和社会经济地位。使用这些模型来估计最佳的时间利用组成（与每个骨骼结果的最佳 5%相关），并在三维四分体图中进行绘制。重叠区域的中心被认为是骨骼健康的黄金日。儿童的时间利用组成与所有骨骼测量指标均相关（p≤0.001，均有意义），除了横截面积（p=0.72）。睡眠、MVPA 较多，久坐时间较少，以及适度的 LPA 与骨骼测量指标呈正相关，除了皮质密度，其与骨骼测量指标呈负相关。整体骨骼健康的黄金日时间利用组成是中心（范围）：10.9（10.5 至 11.5）小时睡眠；8.2（7.8 至 8.8）小时久坐时间；3.4（2.8 至 4.2）小时 LPA 和 1.5（1.3 至 1.5）小时 MVPA。估计的最佳睡眠时间与当前国际指南一致（9 至 11 小时），而估计的最佳 MVPA 超过了至少 60 分钟/天的建议。这项首次描述儿童骨骼健康最佳日常活动持续时间的研究为制定指南提供了证据。
