Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
Medical Research Council Epidemiology Unit, University of Cambridge, Cambridge, UK.
Proc Nutr Soc. 2014 May;73(2):319-29. doi: 10.1017/S0029665114000019. Epub 2014 Feb 19.
High amounts of time spent sedentary and low levels of physical activity have been implicated in the process of excessive adiposity gains in youth. The aim of this review is to discuss the role of physical activity, sedentary time and behaviour (i.e. television (TV)-viewing) in relation to adiposity during the first two decades of life with a specific focus on whether the association between sedentary time, and behaviour and adiposity is independent of physical activity. We identified nine cohort studies (three prospective) whether sedentary time was associated with adiposity independent of physical activity. Eight of these studies suggested that sedentary time was unrelated to adiposity when physical activity was taken into account. Results from studies (n 8) examining the independent association between TV-viewing and adiposity independent of physical activity were mixed. Those that observed a positive association between TV-viewing and adiposity independent of physical activity discussed that the association may be due to residual confounding. A few additional studies have also challenged the general notion that low levels of physical activity leads to fatness and suggested that higher baseline fatness may be predictive of a decline in physical activity. It appears unlikely that higher levels of sedentary time are associated with or predictive of, higher levels of adiposity when physical activity is controlled for in youth. Specific sedentary behaviours such as TV-viewing may be associated with adiposity independent of physical activity but the results may be explained by residual confounding.
大量久坐时间和低水平体力活动与青少年过度肥胖的发生过程有关。本综述的目的是讨论在生命的头二十年中，体力活动、久坐时间和行为（即看电视）与肥胖的关系，并特别关注久坐时间和行为与肥胖的关系是否独立于体力活动。我们确定了九项队列研究（三项前瞻性），探讨久坐时间是否与体力活动无关。其中八项研究表明，当考虑到体力活动时，久坐时间与肥胖无关。研究（n=8）观察到电视观看与体力活动无关的肥胖之间存在独立关联，结果喜忧参半。那些观察到电视观看与体力活动无关的肥胖之间存在正相关的研究讨论说，这种关联可能是由于残余混杂。还有一些额外的研究也对体力活动水平低导致肥胖的普遍观点提出了质疑，并认为较高的基线肥胖可能预示着体力活动的下降。当控制青少年的体力活动时，较高的久坐时间水平似乎与较高的肥胖水平无关，也不能预测肥胖水平的上升。特定的久坐行为，如看电视，可能与肥胖有关，与体力活动无关，但结果可能是由残余混杂造成的。
