Child Movement, Activity, and Development Health Laboratory, School of Kinesiology (SKB Suite 1000), University of Michigan, 830 N. University Ave, Ann Arbor, MI, 48109, USA.
College of Applied Health Sciences, University of Illinois Chicago, Chicago, USA.
BMC Public Health. 2022 Nov 8;22(1):2047. doi: 10.1186/s12889-022-14447-4.
Definitive evidence shows sedentary time (ST) is an independent risk factor for chronic disease, irrespective of physical activity. Despite calls to limit youth ST, studies demonstrate a spike in ST at the transition from childhood to adolescence. Identifying periods of the day (e.g., before school, during school, afterschool, and evenings) during which ST is higher in adolescents vs. children-that is, specifying when within daily routines ST disparities emerge-may be important to inform intervention strategies, as periods of the day correspond with variations in setting and supervision. The purpose of this study was to examine device-assessed ST engagement by period of day and developmental stage in a nationally representative sample of United States youth.
Youth (N = 2,972 between 6-18 years) from the 2003-2004 and 2005-2006 waves of NHANES reported demographic variables and wore an accelerometer for seven consecutive days to determine ST. Linear regression analyses were applied to study associations between ST and developmental stage (childhood or adolescence) by period of the week and weekend days, while controlling for sex, race/ethnicity, annual family income, and body mass index.
Adjusted linear regressions (p-values < 0.0001) showed that adolescents were more sedentary than children during school, afterschool, and weekday evening periods as well as all the weekend periods. However, during school (36.3 ± 7.3 vs. 28.2 ± 7.2 min/hour; b = -7.4 [-8.1, -6.6]) and afterschool periods (31.1 ± 7.7 vs. 22.7 ± 7.0 min/hour; b = -7.8 [-8.6, -7.0]) showed the largest weekly ST disparities by developmental stage. Overall, the during school and after school hours constitute most (during school = 35% and afterschool = 16%) of the weekly ST disparity between children and adolescents.
Our data provide interventionists with estimates of the potential for ST reduction in each setting and period of the day among US adolescents. Future research should gather information about the barriers and facilitators of ST in adolescents by period of the day to help understand factors driving disparities.
有确凿证据表明，久坐时间（ST）是导致慢性病的独立危险因素，与身体活动无关。尽管呼吁限制青少年的久坐时间，但研究表明，青少年从儿童期向青春期过渡时，久坐时间会大幅增加。确定青少年在一天中哪些时段的久坐时间高于儿童（即，确定日常作息中何时出现久坐时间差异）可能对于制定干预策略很重要，因为一天中的不同时段对应着不同的环境和监管变化。本研究的目的是在一个具有全国代表性的美国青少年样本中，按一天中的时段和发育阶段，通过设备评估青少年的久坐时间参与度。
来自 NHANES 2003-2004 年和 2005-2006 年两轮调查的 2972 名 6-18 岁青少年报告了人口统计学变量，并佩戴加速度计连续 7 天以确定久坐时间。在控制性别、种族/民族、家庭年收入和体重指数的情况下，应用线性回归分析研究了 ST 与发育阶段（儿童期或青春期）在一周各时段和周末的关联。
调整后的线性回归（p 值<0.0001）显示，与儿童相比，青少年在上学、放学后和工作日晚上以及所有周末时段都更为久坐。然而，在上学（36.3±7.3 比 28.2±7.2 分钟/小时；b=-7.4[-8.1, -6.6]）和放学后（31.1±7.7 比 22.7±7.0 分钟/小时；b=-7.8[-8.6, -7.0]）时段，发育阶段之间的每周 ST 差异最大。总的来说，上学和放学后的时间占儿童和青少年每周 ST 差异的大部分（上学时间占 35%，放学后时间占 16%）。
我们的数据为干预者提供了美国青少年在每个环境和一天中的每个时段减少久坐时间的潜力估计。未来的研究应该收集有关青少年在一天中不同时段久坐时间的障碍和促进因素的信息，以帮助了解导致差异的因素。
