Janssen Xanne, Mann Kay D, Basterfield Laura, Parkinson Kathryn N, Pearce Mark S, Reilly Jessica K, Adamson Ashley J, Reilly John J
University of Strathclyde, School of Psychological Science and Health, Glasgow, Scotland, UK.
Institute of Health & Society, Newcastle University, Newcastle upon Tyne, England, UK.
Int J Behav Nutr Phys Act. 2016 Aug 2;13:88. doi: 10.1186/s12966-016-0413-7.
In many parts of the world policy and research interventions to modify sedentary behavior of children and adolescents are now being developed. However, the evidence to inform these interventions (e.g. how sedentary behavior changes across childhood and adolescence) is limited. This study aimed to assess longitudinal changes in sedentary behavior, and examine the degree of tracking of sedentary behavior from age 7y to 15y.
Participants were part of the Gateshead Millennium Study cohort. Measures were made at age 7y (n = 507), 9y (n = 510), 12y (n = 425) and 15y (n = 310). Participants were asked to wear an ActiGraph GT1M and accelerometer epochs were defined as sedentary when recorded counts were ≤25 counts/15 s. Differences in sedentary time and sedentary fragmentation were examined using the Friedman test. Tracking was examined using Spearman's correlation coefficients and trajectories over time were assessed using multilevel linear spline modelling.
Median daily sedentary time increased from 51.3% of waking hours at 7y to 74.2% at 15y. Sedentary fragmentation decreased from 7y to 15y. The median number of breaks/hour decreased from 8.6 to 4.1 breaks/hour and the median bout duration at 50% of the cumulative sedentary time increased from 2.4 min to 6.4 min from 7y to 15y. Tracking of sedentary time and sedentary fragmentation was moderate from 7y to 15y however, the rate of change differed with the steepest increases/decreases seen between 9y and 12y.
In this study, sedentary time was high and increased to almost 75% of waking hours at 15y. Sedentary behavior became substantially less fragmented as children grew older. The largest changes in sedentary time and sedentary fragmentation occurred between 9y to 12y, a period which spans the transition to secondary school. These results can be used to inform future interventions aiming to change sedentary behavior.
在世界许多地区，目前正在制定旨在改变儿童和青少年久坐行为的政策和研究干预措施。然而，为这些干预措施提供依据的证据（例如久坐行为在整个童年和青少年时期如何变化）有限。本研究旨在评估久坐行为的纵向变化，并研究7岁至15岁期间久坐行为的追踪程度。
参与者是盖茨黑德千禧年研究队列的一部分。在7岁（n = 507）、9岁（n = 510）、12岁（n = 425）和15岁（n = 310）时进行测量。参与者被要求佩戴ActiGraph GT1M，当记录的计数≤25次/15秒时，加速度计记录的时间段被定义为久坐。使用弗里德曼检验检查久坐时间和久坐碎片化的差异。使用斯皮尔曼相关系数检查追踪情况，并使用多级线性样条模型评估随时间的轨迹。
每日久坐时间的中位数从7岁时占清醒时间的51.3%增加到15岁时的74.2%。久坐碎片化从7岁到15岁减少。每小时休息的中位数次数从8.6次减少到4.1次，7岁至15岁期间，累积久坐时间50%时的中位数发作持续时间从2.4分钟增加到6.4分钟。7岁至15岁期间，久坐时间和久坐碎片化的追踪情况中等，然而，变化率有所不同，在9岁至12岁之间出现了最急剧的增加/减少。
在本研究中，久坐时间很长，到15岁时增加到几乎占清醒时间的75%。随着儿童年龄的增长，久坐行为的碎片化程度大幅降低。久坐时间和久坐碎片化的最大变化发生在9岁至12岁之间，这一时期跨越了向中学过渡的阶段。这些结果可用于为未来旨在改变久坐行为的干预措施提供信息。
