Sedentary behavior in Brazilian children and adolescents: a systematic review

ABSTRACT OBJECTIVE To describe the methodological characteristics of the studies selected and assess variables associated with sedentary behavior in Brazilian children and adolescents. METHODS For this systematic review, we searched four electronic databases: PubMed, Web of Knowledge, LILACS, SciELO. Also, electronic searches were applied in Google Scholar. A supplementary search was conducted in the references lists of the included articles and in non-indexed journals. We included observational studies with children and adolescents aged from three to 19 years developed in Brazil, presenting analyses of associations based on regression methods and published until September 30, 2014. RESULTS Of the 255 potential references retrieved by the searches, 49 met the inclusion criteria and composed the descriptive synthesis. In this set, we identified a great number of cross-sectional studies (n = 43; 88.0%) and high methodological variability on the types of sedentary behavior assessed, measurement tools and cut-off points used. The variables most often associated with sedentary behavior were “high levels of body weight” (in 15 out of 27 studies; 55.0%) and “lower level of physical activity” (in eight out of 16 studies; 50.0%). CONCLUSIONS The findings of this review raise the following demands to the Brazilian agenda of sedentary behavior research geared to children and adolescents: development of longitudinal studies, validation of measuring tools, establishment of risk cut-offs, measurement of sedentary behavior beyond screen time and use of objective measures in addition to questionnaires. In the articles available, the associations between sedentary behavior with “high levels of body weight” and “low levels of physical activity” were observed in different regions of Brazil.

## 摘要
### 研究目的
旨在描述纳入研究的方法学特征，并评估巴西儿童青少年久坐行为相关变量。
### 研究方法
本项系统综述共检索了4个电子数据库：PubMed（PubMed）、Web of Knowledge（Web of Knowledge）、LILACS（LILACS）、SciELO（SciELO），同时在谷歌学术（Google Scholar）中开展电子检索。此外，我们对纳入文献的参考文献列表及非索引期刊进行了补充检索。本次研究纳入2014年9月30日前发表、在巴西开展、针对3至19岁儿童青少年的观察性研究，且需采用回归分析方法进行关联分析。
### 研究结果
本次检索共获取255条潜在相关文献，其中49篇符合纳入标准并纳入描述性综合分析。在该研究集中，横断面研究占比高达88.0%（n=43）；所评估的久坐行为类型、测量工具及使用的截断值均存在较高的方法学变异性。与久坐行为关联最频繁的变量为"高体质量水平"（27项研究中的15项，占比55.0%）与"身体活动水平偏低"（16项研究中的8项，占比50.0%）。
### 结论
本综述的研究结果对巴西儿童青少年久坐行为研究议程提出了以下亟需完善的方向：开展纵向研究、验证测量工具的效度、建立风险截断值、对屏幕使用时间以外的久坐行为进行测量，以及除问卷外采用客观测量手段。在已纳入的文献中，巴西不同地区均观察到久坐行为与"高体质量水平"及"身体活动水平偏低"之间存在关联。