Faculty of Physical Culture, Palacký University Olomouc, třída Míru 117, 779 00, Olomouc, Czech Republic.
Environ Health Prev Med. 2021 Jan 27;26(1):16. doi: 10.1186/s12199-021-00932-6.
Little is known on how context-specific sedentary behaviors (SB) affect adiposity. This study aimed to investigate compositional associations between context-specific SB and adiposity and estimate the differences in adiposity associated with replacing school and out-of-school SB with physical activity (PA).
This study included 336 children and adolescents. Time spent in SB and PA was estimated using multi-day 24-hour raw accelerometer data. SB and PA were specified for school and out-of-school times. Fat mass percentage (FM%) and fat mass index (FMI) were used as adiposity indicators. A compositional isotemporal substitution model was used to estimate differences in adiposity associated with one-to-one reallocations of time from context-specific SB to PA.
Participants spent approximately two thirds of their school and out-of-school time being sedentary. Relative to the remaining 24-h movement behaviors, significant associations between out-of-school SB and adiposity were found in both boys (β = 0.63, 95% confidence interval [CI] = 0.03-1.22 for FM%; β = 0.76, 95% CI = 0.03-1.49 for FMI) and girls (β = 0.62, 95% CI = 0.25-0.98 for FM%; β = 0.80, 95% CI = 0.28-1.32 for FMI). Replacing 30 min/day of out-of-school SB with out-of-school light PA decreased FM% by 10.1% (95% CI = 3.3-17.9) and FMI by 14% (95% CI = 2.7-24) in girls. No significant associations were found for school SB.
A reduction of out-of-school SB in favor of light PA should be advocated as an appropriate target for interventions and strategies to prevent childhood obesity.
对于特定情境下的久坐行为（SB）如何影响肥胖，人们知之甚少。本研究旨在调查特定情境下 SB 与肥胖之间的组成关联，并估计用体力活动（PA）替代学校和校外 SB 与肥胖相关的差异。
本研究纳入了 336 名儿童和青少年。使用多日 24 小时原始加速度计数据估计 SB 和 PA 的时间。特定于学校和校外时间的 SB 和 PA 进行了规定。脂肪质量百分比（FM%）和脂肪质量指数（FMI）用作肥胖指标。使用组成等时替代模型来估计从特定情境 SB 到 PA 的一对一重新分配时间与肥胖相关的差异。
参与者在校内和校外的时间中，大约有三分之二的时间处于久坐状态。与剩余的 24 小时运动行为相比，男孩（β=0.63，95%置信区间 [CI] = 0.03-1.22 用于 FM%；β=0.76，95% CI = 0.03-1.49 用于 FMI）和女孩（β=0.62，95% CI = 0.25-0.98 用于 FM%；β=0.80，95% CI = 0.28-1.32 用于 FMI）中，校外 SB 与肥胖呈显著相关。将每天 30 分钟的校外 SB 替换为校外低强度 PA，可使女孩的 FM%降低 10.1%（95% CI = 3.3-17.9），FMI 降低 14%（95% CI = 2.7-24）。对于校内 SB，未发现显著相关性。
提倡减少校外 SB 以促进轻 PA 应作为预防儿童肥胖的干预和策略的适当目标。
